I will not post comments that are blatant advertisements. While I know the world of PR is tricky right now, I don’t think the purpose of blog comments is to advertise services/businesses. I think the purpose of comments is to advance discussion on a given topic the blog addresses.
I will also not post comments that are off-topic, don’t add to the discussion of a particular post, or are inflammatory in any matter. If you don’t like my blog, don’t read it and don’t comment on it. Your comments will not be posted. It’s that simple.
I believe that each person who runs/moderates a blog can set out their own policy on commenting, and that any is acceptable for whatever purpose their particular blog serves. This is my blog and my policy, and I will not argue it.