We're experimenting with full text search of the federation. For the moment this is both easier to code and easier to host than searching the web. search 
Search Help using the web interface.
Search Findings reported as a Roster of active sites.
This is an experimental service that we expect to change dramatically as we bring more search technology to bear and have more sites to search.
First we will make this interesting, then we'll make it fast, then we will integrate it with wiki itself making the whole federation close at hand.
Future versions will do stemmed and multi-word queries.
Future versions will quote site and page counts.
Future versions will plot page and site networks.
Future versions will be included in each wiki server.