GUESS is a fairly big change to the way searching works on Gnutella. As such, we're working hard to make sure it works right. This means we'll be introducing it incrementally over the next 3 or 4 months, with the first phase starting in a week or so.

You should start to see the initial benefits of GUESS around the middle of January. We wish it could be sooner, but realistically that's about when it will be.