If it's just a link and a couple of lines of text I don't bother clicking onto the link. However if somebody posts a longer summary, or the first part of the blog entry then i'll click across if i'm sufficiently interested. To me ironmanjt is a model for how bloggers should use the TR forum.
In terms of bloggers using the forum, I think it's a matter of giving vs taking. Those who just post links are taking, those who post a decent amount of content are giving. Bloggers certainly can add value to the forum, and many do.