If you have ever played at a Yahoo, you will know that bots plague the site. In recent months, it has become so bad that we would enter a room, say a brief hiya and then spend the next few minutes iggying all the bots (easily identifiable with their 1500 ratings, no games played).
Yahoo has implemented numerous bot control measures over the years. None of them has been successful.
Their latest approach has been to preclude anyone with a provisional rating from being able to chat in the lobby. So far it seems to be keeping the bots under control (and when one does manage to pop in, just use the report spam feature - we did that in one of our lobbies recently and it seems to have been successful).
The downside is that anyone who changes a name or is a brand new player with a provisional rating is unable to chat in the lobby. They will need to play 20 rated games before they can chat. However, Eliters Messenger is available to them and TDs may need to let players know when someone is unable to chat. Even better, invite them to play 20 of the fastest rated games you can muster.
As with everything, it will take time to get used to it. Just hang in there, remember to have fun and if it truly drives you crazy, neither GameDesire nor Pogo suffer from this malady.