Based on recent figures (April 2006), the broadband penetration in the USA has reached 70% among active internet users. This represents a bit over 1% increase per month.
Canada is still ahead although the gap is closing. Currently, about 76% of Canadians have a broadband connection at home.
Korea is still in the lead when comparing the ratio of broadband subscribers to inhabitants. Out of every thousand Koreans, 24 have a broadband connection. That compares to 13 in the USA and 18 in Canada.
Audio and video usage are the main reasons for upgrading to broadband. This creates concerns that sites will find it harder to cope with increased demands. Most popular sites have outsourced the content delivery of video to CDN (Content Delivery Networks) like Akamai.
Alternatives to alleviating the situation are the two-tier Internet proposed by telcos and the rise of P2P networks like BitTorrent.
Update: It seems the average US household now spends an amazing $2,000 on telecommunication services (that includes Internet naturally).