We started investing in blog related businesses early in the development of our first fund and have now invested in delicious, feedburner, adaptive blue, outside.in, disqus, tumblr, and zemanta. We also invested in twitter because we thought it was a quicker and faster form of blogging.

The thesis that blogs were a new form of publishing and self expression is playing out nicely and we are pleased with the progress of our companies and the market as a whole. And I think we are not anywhere near the end game.

via www.avc.com

I think it is mainstream. The data Wilson points to helps make the case. I think a lot of people don't realize they are reading blogs when they land there from Google searches.