One of the cases - Rogers throttling WoW gamers was already covered in my blog (here). A newer one against Rogers, still ongoing, is about throttling VoIP (here).
Another case shows a letter, from Bell Canada to the Canadian regulator (CRTC) admitting their DPI system mistakenly identified web downloads from www.hotfile.com as P2P file sharing and therefore throttling it (here).
While Bell's network management page (here) say they only throttle P2P file sharing - "These traffic management measures impact only those Bell Internet High Speed service customers who are using common peer-to-peer (P2P) file sharing applications during scheduled traffic management periods. Customers using P2P file sharing applications may experience an increase in duration time to download and upload (for Bell Internet DSL) and upload only (for Bell Internet Portable and Rural) files during peak usage periods",