Gmail, google's free email service, has invited a bunch of newcomers in again. According to reports, anyone who has requested an invitation has been given one now, and although the service is still in "beta" (according to the masthead), it appears to be fully functional at this point.
Google caused some waves in the free email world by announcing that it would start a free email service with 1GB of storage per user. Now, most people don't store that much email, but I'm sure there are some who will take advantage of it.
The key features of the service including Google's search capabilities as well as a cooperative spam-watching technique that is rumored to take advantage of the ability to go back into somebody's unread mail and mark as spam something that has been delivered to the mail box before the voting system determined it was spam. If this is true, it certainly will make for one of the most effective spam detection mechanisms available. To further add to that, Google can watch email messages being delivered to gmail accounts and see how many are identical or near-identical, further enhancing spam detection.
One wonders if they will be competing in the spam detection field soon.