Here is a link to a blog about the language of blogs by a great linguist - Greg Myers.
The blog has developed into a new book which, if his previous work is anything to go by, will be an interesting read about how meaning is negotiated online and how traditional relations of power are challenged by new modes of publication.
I first noticed Greg Myers' work from his article in Applied Linguistics called 'The Pragmatics of Politeness in Scientific Articles' in which he discussed how scientific knowledge is transformed at least as much as the result of pragmatic, social factors as so-called scientific factors.
Also on Greg's blog is a list of linguistics and language-related blogs. I will try to find some time to see what other linguists have to say on their blogs.