Copyright Alert System
The CAS will take content that people might be pirating, like a blockbuster movie or popular album, and looks for computers that are uploading it using peer-to-peer filesharing software like BitTorrent. That person's IP address is visible, and his or her ISP knows which account is associated with that address... The first two times, you just receive an email and a voicemail saying you've been caught. The third and fourth times, you're redirected to some "educational" material, and you'll have to click that you understood it. The fifth and sixth times, it gets serious: Your Internet connection can be slowed to a crawl for a few days... This is bad, possibly devastating news for the OpenWireless (Sharing [[WiFi]]) Movement, which encourages people to keep their WiFi open to neighbors and passersby as a public service. But as you now, the CAS wants to stress that anyone who pays for a connection is responsible for what happens on it.
EFF notes https://www.eff.org/deeplinks/2013/02/six-strikes-copyright-alert-system-faq