I truly have n idea but know it has to be over 10. I am a member of mylot,spark people,crochetville,platinum lounge,hot oupon world and that is just a few. Do you have any idea how many you are a member of?
I can't remember, may be 10 or 12. I am a member at mylot, orkut, myspace, hi5, friendcircle, taketopics etc. I can't remember all.
If you ask me the active communities then I can tell you that I am active at mylot, orkut and taketopics only.