Mike (vazco)'s plugins:
Without any modifications, this plugin allows you to define search terms which user can later check on the search page. You can f.e. list the tags that are the most important on your site.This plugin also contains a set of quite usefull and powerfull methods of enchancing search process, eg. sorting users by weight of a search terms or ability to extend search criteria. Those last features are very not user-friendly though, don't use them unless you really know what you're doing.
To install the plugin, you will need to copy one file to your Elgg's core. Please read teh readme.txt for details.
Compatible only with Elgg 1.6.1