Since the announcement is now gone I'm pasting my reply about the Beta Search:
It was in the announcements above the Technical Issues Forum, but that's now gone.
I posted this a while ago in
Three-Letter Search Not Working! thread:
The Beta test search has been turned off as the default search. To use it you have to go to the bottom of the advanced search page and use the "Search Forums -- IB Beta Search" form.
This was covered in the announcement above all forums.
EDIT: Three letter search (such as airport codes) can be used as search term(s) in the Beta Search.