Probably that lots of people are logging in and checking there mail.
If the number is higher than the number of people that have accounts, check the network and see if connections are coming from subnets on the Internet which you don't expect them to be coming from. If they are, block those subnets.
Last Wiki Answer Submitted: Apr 30, 2008 6:39 AM (GMT) by Mrdenny 63,630 pts.