My advice is based on what Google provides to webmasters:
When it comes to a blog earning page rank hat's by far more important is noting that:
(1) Google does not place high value on reciprocal links;
(2) Google places even less value on reciprocal links to unrelated blogs;
(3) If your web pages and the site get a lot of reciprocal (two-way links), especially if they are not related then the search engines will assume that these are solicited links, and search engines do not give much importance to such two-way or reciprocal links and may even penalize your site. That's why posting a thread soliciting reciprocal links here on a forum where every thread is indexed by Google is something I wouldn't be doing;
(4) Google does place high value on the backlinks within posts to directly related posts in blogs in the same niche. In other words, Google is looking for natural linking patterns.
If you don't like the fact that we can all post into any thread here as long as what we post is on-topic and does not violate the rules of conduct then that's unfortunately something you will have to deal with.