Blogs are a good answer for the question "how do I post?", but not a good answer for the question "how do I read?". Most people want some kind of aggregator. There are many aggregators out there, but if the answer to the question "how do I post?" is different from the answer to the question "how do I read?", then most people won't overcome the technical friction. Facebook, Twitter, etc. solved the problem by answering both questions, along with other important questions like "how do I restrict who can read my posts?" and "how do I bring in my friends and family?".

I'd really love to see a resurgence of blogs, but any replacement for Facebook needs adequate answers to the kind of questions that blogs always left unanswered.