I think it's because my experience has been providing services to small businesses who do business primarily locally.
The web is where they can compete with big companies. In traditional outbound marketing and advertising, they couldn't. But, on the web, in their area, they can win because they can focus their online marketing dollars and activities on "Birmingham, AL house designs", for example. Whereas the big guys won't be able to focus on just one city as intensely.
But, this has been just a theory for awhile. It is a rare small business that has been doing this for years.
But, now it's possible for small businesses to compete without any outside resources. The tools are available and the knowledge is digestable and it's all at the right price point. Small businesses can bring their marketing in house, and measure their return on time spent.
The big reason for this is "Local SEO".
Two of the guys that are more obsessed than me just released their "Local SEO" predictions for 2008: Andrew Shotland and Greg Sterling. Worth reading if you don't want to take my word for it - that this might be the year of the small business on the web.