[citation][nom]technogiant[/nom]simple...use a VPN....then the isp can't see what your traffic is.[/citation]
It's not as simple as that. Both ends of the connection have to be involved in order for a VPN connection to exist. You don't just flip a switch, virtual or otherwise, labeled "VPN" and all of a sudden your connection is secure for monitoring. The problem with P2P connections is that they utilize the "other" ports. By that I mean, all of the common Internet services, such as web, email, ftp, telnet, dns, etc. all have known "official" port numbers. Commonly used communications software, games and such, also have known port numbers. The P2P software, which can use different, user-specified port numbers tend to be in the other category. This makes it a lot easier for that traffic to be singled-out. Deep packet inspection can then be used to ascertain the content of packets; and the same technology which is used to help ISPs mitigate the propagation of malware can be used to mitigate P2P traffic.