Blogging about blogging, podcasting about podcasting...
As Shel and Neville have suggested, it's just the evangelism process at work. We business communicators who DO 'get it' are trying to 'beat the drum' so that those who 'don't get it' might finally pay attention.
I find blogs are, yes, online journals. But they can be and often are so much more.
In the Cluetrain spirit, blogs and podcasts are amazing opportunities for companies to better manage their knowledge, spread their PR activities wider, develop a genuine 'voice' that can interact with the public, elicit feedback from customers, clients and the public, allow people to 'time shift' when they hear news about their product or service a business provides, and much more.
If any of us are guilty of incessantly talking about this new medium, it is because we are excited about its possiblities. Forgive us, but we genuinely believe blogs and podcasts can add substantially to the communications mix for any company.