this is the thing - from the way f9 are going they want to get rid of any user using above 10gb a month during peak times. This is a bad PR move IMHO, but then again some will say its a good move.
Remember with all the new multimedia equipment being sold by high street stores, that stream both video and radio broadcasts from the net, along with the bbc, sky, channel4 etc allowing the streaming of video content, F9 will need to look at the bandwidth allocations as 15gb a month would be nowhere near ample to sustain this.
IMHO if F9 are so against people using the internet as it was intended they they should block everything except for standard html and email, as this is near enough what they are doing by throttling users.
In all F9 should be providing the service you pay for - if you pay for 1mb connection but only getting speeds of that of a 56k modem then you can cancel the agreement as they are not supplying you with the service you are paying for...