Previous issue, closed because the tag cloud link was on the home page. http://codeplex.codeplex.com/workitem/25269
There are about 25 tags available on the directory page, but I have not been able to find a way to start a search using a tag other than those 25 or so. If one gets a search results set via a text search, and if those items have tags, one can narrow one's results set by clicking on an item's tag. But I don't see any way to start out by finding (for instance) all items tagged with "project server".