You can search for posts by username, by date or by keyword(s) in the post body or subject.
To access the search feature, click on the "Advanced Search" link on the right-hand side of the page or use the "Quick Search" field located above every threadlist.
All existing forums that you have access to are automatically searched, i.e. the search is not restricted to the forum that you last visited. You will not be allowed to search through private forums unless the administrator has explicitly authorized you to do so.