i downloaded firebird after jon udell mentioned the ability to add custom searches. the browser itself is severely lacking in polish. but the extensible search capability is nice. it's something that should have been standard in browsers since 1996. that was when a company called privnet (later bought by PGP) released a hack to both netscape and internet explorer called anysearch that added this very same functionality. that was seven years ago, and the browser world is just now catching up.
the only reason i remember all of this was that anysearch was not particularly user friendly (but firebird's search feature is). i took the time to figure out how the important information was stored in anysearch's undocumented and mostly binary format and wrote some more searches to add to the default package. i thought other people might find the searches useful, so i put them online under the name "anysearch extras" and notified the mac resource page (which amazingly still looks today almost exactly how it did in 1996). this was my first software, and as far as i was concerned, i became famous overnight. (anysearch extras is currently google result #44 for my name). i don't even remember how many people downloaded it, but it was enough to make a big impression on me at sixteen years old.
interestingly, in a search for "anysearch extras", the first result is a link to an unauthorized server i ran (from an ip address - which i still have memorized) on my mac (8600 ppc) over a dialup connection from my home. the ip address hasn't been an active server for seven years, but google hasn't given up yet.
anyway, my point is that the technology has existed to offer this simple functionality for seven years, and the only reason it hasn't become standard is that no (browser or plug-in) developer has provided a documented format for search engine descriptions, probably for fear of losing control over a potential source of income. a general lesson here is that people can constrain innovation as much as or more than technological barriers. so if users want innovative software, in the long run the social politics of a company can be more important than the company's technological achievements. this is a lesson too many consumers haven't learned.