And my guess is Facebook.
Is it because thoughts and opinions started getting channelised on FB status messages? Or for that matter twitter. Or is it that you feel the presence of people reading what you post, so it preempts you to be more active on FB rather than on the blogosphere...
Has this happened to you? Back in 2004, so many of us used to blog, and regularly at that. Not so much anymore.
Or would you just like to call blogging a phase?