Is This a Permanent Solution?
Maybe. If a significant number of mailtos become unusable, spambot programmers will add functionality to handle that. Unlikely. This utility is not exactly well-known, and as you can see, it takes effort to do a single link, so doing a page with lots of mailtos by hand or a site with a mailto: per page would be very tedious. If web authoring tools had "use alphanumeric codes for mailto:" or "convert existing mailto: to encoded" as an option, more sites would do this. I personally compose HTML in Wordpad, so I am unfamiliar with current web-authoring tools. (If you know about one that supports encoding mailtos, please let me know.) Programmers should consider adding these options to authoring tools.
Of course, there's always the chance that somebody will add it just because he can. Doing this works for now, so it's a good idea. It's a freeware utility and there's no known downside to using either the utility or encoded mailtos. If you need to add mailtos to your page after processing whole pages, use the Hyperlink Wizard (refer to Figure 5), copy to the Clipboard, and paste into HTML where indicated on the page you want changed.