See this GovGirl piece, Is Government Blogging Dead? Personally, I don't think so — not yet anyway. Certainly podcasting has come on strong in recent years, but I can't see "ultra short" podcasts taking off anytime soon.
The biggest issue for people thinking about blogging is committing to being consistent in doing blog posts and having something meaningful to say. You need to have an opinion, or why would people tune into your blog? Much of what I share is informational in nature, but there are opinions to go with the news or events.
Don't start if you are not ready to continue the effort.