They don't really "do" anything. I assume they exist on our pages so we can find people with similar issues, just as writing about our interests can make us find people with similar interests.

I can feel you also question putting them there. It's good to know. I just thought it's what people do, I didn't put a deeper meaning into it. Now I realize such a simple thing means stuff to other people. And that I somehow managed to fail understanding that. And that I did something wrong without knowing or understanding.