Naturally, the blogosphere is seeing things through a blogo-spherical lense, and to them it's huge, no point in debating that.
But the world is a lot larger than blogs and I think that's why they miss the point entirely. 99% of all the blogs out there is rubbish anyway, or at a minimum has very limited applicability. A 'rating' system for blogs would actually be a useful thing but I see it very much as a niche application.
And don't forget that the rss stats from the google bought 'feedburner' also tell you a lot about blog popularity without having access to 'twitters goldmine', same goes for analytics. Google has a lot more when it comes to datasources than just the search box.
So does Google (links coming in, perhaps even twitter links) also they use user click data; Google knows son, Google knows.