Home > Articles > Web Services > XML

RSS Clustering: A Unique Approach for Managing Your RSS Feeds

Content syndicated via RDF site summary (RSS) feeds is a great feature of the Net, with one big drawback: WTMI (way too much information). Jose Nazario discusses a custom RSS aggregation approach that allows the user to handle large volumes of RSS data, as well as find interesting trends within the flood.
Like this article? We recommend

Like this article? We recommend

The rapid growth of RDF site summary (RSS)feeds has facilitated the consumption of information that has been part of the promise of the Internet. RSS, a standard XML format that works well for dynamic sites such as blogs and news outlets, enables consumers to easily digest updated information without having to periodically visit every web site they track. One consequence, however, is that many RSS users are unable to manage their feeds easily due to an overwhelming number of new stories. For subjects such as world news, many of the stories are redundant, adding a burden to readers to sort out which stories they've already read. To deal with the twin problems of flooding and redundancy, I've developed an application that reduces the number of items to read and uses the overlapping information to divine interesting topics. In this article, I explain how my prototype system gathers, distills, and presents world news in order to give the reader a more pleasant and efficient RSS experience.

Organizing RSS Feeds

The growth of the quantity of content on the Internet is due in no small part to the ability of any user of the medium to publish to a wide readership, with little effort, at a nominal fee. This revolution in the ability to communicate to a broad audience is as sweeping as the development of the Gutenberg press, with published material that's significantly more accessible to the average world citizen. As a result, the amount of content that a savvy Internet user will want to view as a steady stream can grow substantially. Automated tools have been developed to facilitate this process, helping to ease the burden of keeping current.

RSS Aggregators

RSS aggregation, the process in which various RSS feeds are collected and presented to the user, is typically used as a means of gathering and browsing large amounts of information efficiently. This technique works well for sites that regularly update or change their content. To collect and view these RSS feeds, an application called an RSS aggregator is used. A variety of these aggregators exist for Windows, Mac OS X, and various open source systems such as Linux and BSD. However, the scalability of these RSS aggregator tools is rapidly challenged when a user attempts to monitor more than a few dozen sites using the approach offered by first-generation RSS aggregators. First-generation RSS aggregators are much like an email or a Usenet client, presenting information in a spiral fashion: feed, headline, story. Second-generation RSS aggregators integrate more closely with a web browser, but suffer from similar problems. They also have the more visible difficulty of competing for a very small space in the browser toolbar, which often doesn't have room for more than a half dozen feeds to be front and center.

A typical RSS aggregator has a layout similar to a Usenet reader or a mail user agent. As shown in Figure 1, this model uses a three-pane layout, with navigation typically going from the list of feeds (panel 1) to the list of headlines or stories for the current feed (panel 2) to the extracted entry for a particular title (panel 3). New articles are typically indicated by highlighting the feed and headline.

Figure 1

Figure 1 Layout of the user interface of a typical RSS aggregator application. The feeds list is often on the left side, but sometimes at the top. The stories within any single feed are usually listed in a window above the individual entry being viewed.

The main goal of an RSS reader is to automatically gather content from dynamic sites and highlight new material (see Figure 2). The RSS aggregator application automates this process by periodically polling the subscriptions that the user has chosen, looking for new material. While this system works well for a small number of RSS feeds, this usage model quickly breaks down when the number of feeds grows to several dozen or even hundreds. Under these circumstances, the stream of new content is transformed into a flood of material, and the aggregator tool has automated the gathering of more material to read. Because an RSS reader gathers material that the user requests, it's reasonable to assume that the user may want to examine all of it. However, a typical human reaction to information overload is to began "triaging" material—discarding it or skimming it rapidly. In both cases, information is lost. Furthermore, the information is usually presented without any semantic tags to indicate which material offers the highest value. The user is left to make that determination. Finally, for feeds of a similar nature (news feeds concerning global events, for example), a significant amount of redundancy exacerbates the problem.

Figure 2

Figure 2 The RSS aggregator uses color to indicate which stories have not been read (red) and which have been read (black). Individual feeds are indicated as blue boxes.

RSS Clustering

As a means of improving the scalability of the RSS aggregation approach, I have begun performing second-order analysis on aggregated materials to make use of the redundancy in the information. I dub this technique RSS clustering because it groups stories by topic (see Figure 3). The redundancy observed in any collection of RSS feeds can be used for two main purposes:

  • Highlighting the interesting bits of news within a pool of feeds. This scheme is based on the assumption that the appearance of the topic in multiple entries is proportional to the importance of that topic.
  • Clustering entries around these topics. By clustering the entries, we reduce the volume of information presented to the user at any one time.
Figure 3

Figure 3 Stories that are related by a common topic are grouped to indicate their relationship and to streamline the RSS reading process. These stories are pulled from individual feeds.

This technique is not new or novel; it has been demonstrated by sites such as Google news, Topix.net, Daypop, and to a larger extent Popdex and Blogdex. All of these sites aggregate dynamic content and use a set of popularity heuristics to determine topics and content found interesting by the community at large: the news publication community for news sites Topix.net, Daypop, and Google; and the blog publication community for blog sites Blogdex and Popdex. This setup acts as a collaborative filter mechanism.

Topic Mapping and Its Relationship to RSS Clustering

The basic concept behind RSS clustering isn't novel, although this implementation is believed to be one of the first openly described systems to perform such an analysis. One of the roots of this approach lies in topic maps. Topic mapping uses a similar approach to RSS clustering, but is much more mature. It provides an efficient way to identify related material within a large corpus of data. When visualized, topic maps show occurrences on the basis of topics.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020