Thanks Cultiv8r,
From your reply it sounds like Cable and DSL are widely available and that that basic wide-band packages are pretty cheap - as you would expect from the huge volume of the market in the US.
Some regions like South America - where most countries don't yet have the necessary infrastrucure and are suffering economic and political problems - could potentially explode as net / P2P users in the next few years. For example, I read recently that the number of connected users in Bogota (Columbia) has risen spectacularly in a couple of years.
People without at least a flat-fee 56k connection (ie. not per-minute rates) are not going to leave their client open for people to upload, neither will they be doing much downloading anyway. It's obvious that any serious user needs a wideband (cable/DSL) connection and people will not subscribe to these massively unless they are widely available and reasonably priced (as they obviously are in the US).