Not only is it quite easy for a customer to quickly rack up a farily hefty data tab just by watching a few shows online, the recent upgrade to bump up quality will hit smaller ISPs more than the big boys.
The problem is due to the BBC switching its content delivery network supplier. A content delivery network caches large files, like TV shows, near to where people that want them are, so it costs less to shift them around.
The BBC is switching from Akamai to Level3. Akamai makes money by charging media companies to cache content and allows ISPs access for free. Level3, on the other hand, will only exchange traffic with big players for free – making smaller operators cough up for the privilege. As a result, the change is unlikely to have any effect on the likes of BT or Sky, but make things more difficult for the smaller operators.