GirlsAskGuys = GAG = G@G These are just abbreviations for the site's name. GAGers/G@Gers is what we call the users/members (you).
Followers are GAGers who Follow you. You can view that list by clicking "Follows" from your account menu (top right), or from your profile page. You can Follow other GAGers by clicking "Follow" from their profile page, or by clicking the plus sign from the hover box (when you hover your mouse over their username in a thread).
It used to be girls ask guys. A question and answer forum, like Yahoo answers, but, recently, it's turned in to, well, Twitter. And, girls ask girls... as I've seen most girls start asking girls only questions (les, bi) etc..