Not sure where that is from..but it should be seen when one registers and also as a "sticky" at the top of the forum here.
Many forums also have a company/vendor section in their forums. They have no problem with such posts...as long as they keep them the appropriate section.
Edit..I now see where it says that. Seems no one sees it at the top unless it's bumped to the top...? That needs to be fixed. Put that info in the "Rules" section as well as when one registers..then it'll all make sense