it's all bull
Yes, our traffic is logged but if suspected of streaming live footy they can throttle but not stop your broadband, they can block known IP's from being accessed which is why it would go black. two of us could both be with same isp and both watch the same match every week, it goes blank for one of us and not for the other. It's not because the users been throttled, it's because their IPTV feed has been blocked while the other users IPTV provider has not.
To see exactly what you are doing online they need a warrent.
Sites that
@basejumper mentioned does not get this information from ISP's, it is either obtained from some trojan on the users computer or obtained from torrent servers etc.
Yes, I had loads of letters about my usage when I was downloading MP3's to burn to CD's back in the 90's yet never had any since streaming in the past 5 or 6 years