The Guardian has an interesting article Blogging : The long and Short of it, which looks at how over the last 6 months that blogging is becoming less popular. The arguments are pretty much on the money. Saying :-
Where is everybody? Anecdotally and experimentally, they've all gone to Facebook, and especially Twitter. At least with Twitter, one can search for comments via backtweets.com – though it's still quite rare for people to make a comment on a piece in a tweet; more usually it's a "retweet", echoing the headline. The New York Times also noticed this trend, with a piece on 9 June about "Blogs Falling In An Empty Forest", which pointed to Technorati's 2008 survey of the state of the blogosphere, which found that only 7.4m out of the 133m blogs it tracks had been updated in the past 120 days. As the New York Times put it, "that translates to 95% of blogs being essentially abandoned".
I think it maybe true. I've noted how I've increased my RSS feeds and get less Blogs.