To bolster BigMC's advice, I've done a little poor man's analysis of the member pool here at GetBig.
There are 47,656 registered members. Of those:
- 35,499 (74.5%) have ZERO posts. None.
- 41,174 (86.4%) have less than 10 posts.
I am sure that you can get some great stats on "Last Post Date" to really understand that the person that registered the account IS NOT COMING BACK, and if that account is used, it was password-cracked and is now a gimmick.