Search Macros are a clever technique that gives the user the ability to assign a simple trigger for sophisticated search behaviors. For example, the "livesearch.reference" macro triggers the behavior of restricting the search to reference sites, in this case by presumably expanding the macro into the expression "(site:wikipedia.org or site:about.com or …)". A very convenient shorthand that I can see coming in handy in even everyday searches.
This feature has been around for the past several months, but the Live Search team is now taking it one step further: each search macro can have its own homepage, creating a bookmarkable search homepage for a huge range of potential customized search engines. Zach writes about the Reference Search Engine, the MSDN Search Engine, and my favorite, the Video Games Search Engine. but you could imagine thousands more being created.
And that's where the power of the masses come into play. Microsoft also launched a Gallery of Search Macros, where users can come together to share and discover useful customized engines. By offering tools for users that that can be customized, Microsoft can learn about topical areas of content and interest, and ultimately weave this back into better tools for the user. This is part of what Microsoft's Ramez Naam considers the virtuous circle for the search ecosystem, and it is something that could have a far reaching impact on how we find and discover information.
And, as an added bonus, every single search macro page has a link to a corresponding OpenSearch description document so they can be used in the search box dropdown of the next generation of web browsers. (Here's one for the video game search engine.) Just in time for tomorrow's launch of IE 7!
Congrats, guys. Nice work!