I know many smaller ISPs that offer similar subscriptions and charge about the same for downloading additional content. The theory is that your average consumer doesn't download more than 4 - 5 gigabytes of data each month, but of course that was before the advent of youtube and hasn't taken into consideration IPTV or legitimate movie downloads.

Of course these same providers also offer un-metered internet at a higher cost or if your broadband is bundled.

Actually I've also seen what happens when it all goes pear shaped. A friend from work got a $320 telephone bill (instead of the usual $60) after his daughter discovered bittorrent. I tried my best, but ultimately failed, to not laugh.

The thing is the people that say subscribers will ditch the service are dead wrong. At the moment the number of users that download more than 5 gigabytes of data a month is still very low. The general public tends to use the internet for Amazon, Google and email and not much else.

But even when people realise they're being metered, there's no evidence they switch providers. At least not so far and not when unmetered alternatives are available from the same company.