Here is an interesting post about how one company, Glance Networks, found that their business service (desktop sharing) was affected by Canadian ISPs’ crude attempts at traffic shaping (throttling).
One day a few years ago, our support line got a spate of calls from customers complaining that our service had suddenly slowed to a crawl. We soon realized the problem was localized to Canada, where nearly everyone gets their Internet service through one of just two ISPs. Sure enough, posts on blogs indicated that both of these ISPs had secretly deployed “traffic shaping” methods to beat back the flow of BitTorrent traffic. But the criteria their methods used to identify the streams were particularly blunt instruments that not only slowed BitTorrent, but many other high-speed data streams sent by their customers’ computers.
This experience illustrates why additional rules need to be imposed on ISPs. While we were working the problem, customers were understandably stuck wondering who was telling them the truth. Their ISP was saying “all is well” and that “nothing has changed”, both of which turned out to be wrong. But how were they to know? Their other Web traffic flowed normally. From their perspective, only our service had slowed.