The search syntax is:
Query:option:optionvalue
The query can be text in a listing title and/or description
The options are: Build, User or Version
Build is the numbered build of the site, i.e. 2.1.xxxx.xxxx
User is the user who made the post, i.e. Nick
Version is the string value of the build, i.e. 2.1 beta 2, or 2.1 RTM
You can only put one option in the query, javascript is a bit funny with this.
Example: "community server:version:2.1 Beta 2" or "Reszler:user:the wizard" or "MVP:version:2.1 beta 1"