Blogs are awesome. They can be educational, entertaining or, in my case, a tool for the author to learn how to write better.
Blogs for SEO are asinine. I’m only referring to blogs that are tacked onto a site simply to keep the home page fresh and provide more copy for search engines to consume. As a consumer, they’re annoying and as a developer they’re dishonest.
If you want a blog to post periodic updates about your company/service/product then fantastic. Blog your face off. If you want a blog to create more copy for search engines to consume then please go die in a fire.