3241 people have me in my circles and I don't know why

I don't know if this is a common occurrence, but it seems that 3241 people/(accounts) have added me to their circles, whilst my own circles consist of 12 people. I hardly use g+ but the accounts seem legit. Do I put friend-recommendation algorithms in panic mode, have I been "circled" by a very social botnet, or is there another reason why I have 3241 followers?