There is no advocacy group, at least none that I am aware about, there is some other forums external to the Sabayon Official Forums. But I don't think they are the same thing. Most of the word spreading is done by blogs and something like this.
Thank you very much for welcoming me to the community. I am quite surprised there isn't a unified effort of evangelizing Sabayon Linux as it has been so amazing thus far as a linux distro for me that I put it on several of my computers, the only other OS that I can say worked like this was PC-BSD, with a little work. If anyone is interested in creating some type of "Official" advocacy group I would like to take part. There are a couple of decent examples and both openSUSE and Fedora call them Ambassadors: