thecoalman - 6:08 pm on Jul 10, 2011 (gmt 0)
Member lists are not purged on some sites and are usually bloated with accounts that never finished the activation or if they did finish never used it.
I purge the registered accounts on my forum every few months, anyone with 0 post account with no activity in six months is removed. Those that have been purged make up 50% total that have registered. If you threw in the spammers that have registered and posted its probably goes up to 60%
Looking over some stats of those remaining on the list active members is probably in the 20% range if you wanted to consider the beginning of May as being active.