There are currently 50.2 million broadband subscriptions in the US. According to the latest report., broadband adoption jumped 33% last year. What is interesting is that DSL was more popular than cable. DSL has the advantage of costing significantly less than cable, although the speeds aren't comparable with the more expensive cable services. The rise in broadband adoption can be linked with the popularity of online video sharing services like YouTube and Google Video which depend on a fast connection. I know I could not do my browsing and work on the web with dialup. The high quality content of todays internet just oversaturates dialup connections.
For those still on dialup, I pity you.