After 15-18MB of transfer, Comcast throttles your download speed from previous 2.2MB/s down to ~750KB/s.

They had better not mess with corporate VPN users. I assure you if any companies IT department has to eventually learn that the connection problems were Comcast throttling the corporate employees connection there are going to be lawsuits.

If you think your iSP is not meddling in this Internet Throttling scheme, check out this website :

http://www.cfos.de/speed/documentation/speedlist_e.shtml

The software for internet shaping listed all their customer - almost all ISP doing this :p

If the user fully utilize the bandwidth that he/she pays for, and the ISP network slows down, the ISP either upgrade their bandwidth, or dont advertise and try to sell bogus 'high speed' internet packages. That's fraud at it's finest level!

Talktalk do it in UK too. I've seen it on a friend's connection. He has blistering speed, then we fired up a p2p to download Linux and the speed ground to a halt. A few moments after closing the p2p application and all was well again.