I thought I would give it a try. I have gmail and use Picasa. I signed up and invited my son who is a Yahoo user and had previously refused to gmail. He accepted and we tried to communicate managed it by mail but not yet speech and I cannot get into Talk at the moment although GMail works fine.
Can't get GT to work unless I disable Norton Internet Security, even when I choose to allow it when a Norton warning screen comes up on Startup. When it works, it's great - good sound quality. I'm on Windows XP home.