It was disabled to conserve space. A mere few days ago, the TMF's database grew to the point that it overloaded the hard drive it was on. THe TMF was moved to a larger partition, but to keep it under that limit, Search and PMs were disabled while a solution was found. That solution (Kulling posts in the Humor Subforum), gave the TMF new breathing room, and PMs were restored quickly. Search is likely to return soon.