Comcast will implement a 250 GB data monthly cap on customers starting Oct. 1.

The move, reported first by DSL Reports, was confirmed by Comcast today (Techmeme). On its site, Comcast posted its amended user policy:

We've listened to feedback from our customers who asked that we provide a specific threshold for data usage and this would help them understand the amount of usage that would qualify as excessive. Today, we're announcing that beginning on October 1, 2008, we will amend our Acceptable Use Policy (AUP) available at http://www.comcast.net/terms/use/ and establish a specific monthly data usage threshold of 250 GB/month per account for all residential customers.

250 GB/month is an extremely large amount of data, much more than a typical residential customer uses on a monthly basis. Currently, the median monthly data usage by our residential customers is approximately 2 - 3 GB. To put 250 GB of monthly usage in perspective, a customer would have to do any one of the following:

* Send 50 million emails (at 0.05 KB/email) * Download 62,500 songs (at 4 MB/song) * Download 125 standard-definition movies (at 2 GB/movie) * Upload 25,000 hi-resolution digital photos (at 10 MB/photo)

This is the same system we have in place today. The only difference is that we will now provide a limit by which a customer may be contacted. As part of our pre-existing policy, we will continue to contact the top users of our high-speed Internet service and ask them to curb their usage. If a customer uses more than 250 GB and is one of the top users of our service, he or she may be contacted by Comcast to notify them of excessive use.