There is nothing worse when feeling very low then using a support forum and seeing other people replying to each other while ignoring almost any comment you make. You then try to reply to others to be more emphatic and often still get ignored. Of course if its a social anxiety forum the people there are probably more likely to ignore you and not reply than any other type of support forum. Thats why it often doesn’t help for those with the worst anxiety and often makes you feel even more lonely and more depressed. The popular people on such forums are always the ones who appear the most normal and show the least amount of anxiety (online anyway).
Exposure to such forums does not teach you how to behave or makes you better but makes you want to give up. This happens in real life too of course in that if you keep acting anxious, keep making a fool of yourself in public situations your anxiety gets worse and not better and you hide away.