Whether it is visible to me all the time or not doesn't matter in my opinion. Of course it can be blocked, but the forum software is still putting advertisement links onto keywords in the posts users make. They are in your posts, they are in my posts, boomer's, Dave's and everybody elses posts if they contain certain vocabulary.
I'll say again that I think that is fine if it is applied to articles, product reviews or news posts that are released in an official RD forum kind of way. If that is the image that RD wants to portray within their messages I have no issue with it.
To allow it to be acting on user posts is not alright however, because as a user I did not agree to advertise third party businesses within my utterances. In fact, the forum rules explicitely state that any form of advertising is forbidden. I do not put ads on my video uploads on a certain popular site either, because it is my choice not to do so. They asked me, I chose. If you go into my post on the first page of the RC6 release thread, where I mention some PC hardware bits, it now links to an online shop - I'm not a spam bot who hides links in his messages, so why does RD make me look like one now?
Put ads on the front page, the site background and so on, if you have to - but leave the discussions and exchange of information free of it like any decent forum does.