Today when reading on ActiveRain I came across a question and answers and while there were a lot of answers, none indicated where I believe the answer can be found... the community guidelines. I seem to recall a time when they were easier to find and I might be missing a link somewhere. But if you use the sitemap link at the bottom you will find the "COMPANY PAGES" The screen shot here is what displays. The Community Guidelines, Weltanschauug and Terms of Service set for the rules of engagement for member to member comments.
Now like the English language I feel like all rules have exceptions. From time to time I've seen a blog post that was in the form of a question and sometimes the answer to the questions has been very well explained in a blog post and I might use a link to that post in the event of that exception. But if it in anyway can be considered to be promoting my business I don't do it and I don't allow it to be on my blog post in the comments.
There are some really OLD posts on the Community Guidelines in the form of links to blogs on the topic. If you haven't read them I suggest when you have a little AR reading time you try to fit one or two in once in a while. Great reads and good rules to blog by.