Everyone (?) knows that Community Server uses Lucene for its Enterprise Search. The one problem I found is that I couldn't find any search syntax documentation in the CS Docs. Here is a list of all index fields that CS uses:
app: (forums|photos|files|weblogs)
applicationkey: The application key the post is in
applicationtype: (Forum|Gallery|FileGallery|Weblog)
attachementname: Any attachement name
date: The date the post was made
user: The username of the poster
userid: The userid of the poster
settingsid: The settings id the post was made in
groupid: The group id the post was made in
sectionid: The section the post was made
threadid: The thread id of the post
parentid: The parent post if
postid: The post id
name: The name of the post
title: The Title of the post
body: The Body of the post (stripped of HTML)
rawbody: The Body of the post
tag: The tags on the post
tagkeyword: the lowercase version of the tags
url: The relative URL to the post
role:
exact: ?
link: ?
To search on these fields, just user something like "user:CarKnee" to see all carknee's posts.