Here is a site for gifted adults that was formed when the SENG forum board closed:
http://mygiftedlife.org/I used to be involved with that when it first started up, but it is mostly gifted adults and I wanted more of a parenting board. I guess I find I have more issues as the parent of a gifted child than as a gifted adult myself. So, I'm happy here. But the group on mygiftedlife is a good group of people, so you might want to try that if you are looking for adult conversation, debate over unique needs of giftedness and adults, intellectual discussion of issues, etc.