There appears to be a bug in the mod that it will show and count partial registrations (namely those from social networks). What it will do is show a comma at the beginning of the who was online list but since it's a partial registration it will do nothing more but it counts it as a member online today.
The mod should only count active, completed accounts.
This freaked me out to see it the other day as I thought it was some sort of security breach and submitted this to IPS in a hell of a crazy tizzy this weekend because I've never seen this happen before. You can trust I was going insane.
Thanks!