So, what I know, the button take the server you add on a list. You add it, when you don't like the server or what ever. And when you search for servers, you can see the added server easier.

I never used it so far, so i can't tell you 100% correct, sorry.

What killerkeks wrote. It makes it easier to see which server you don't want to join for whatever reason. It's really helpfull, especially combined with local comments.

jbomb99 wrote:

Thanks for the responses so I can assume it is the same funtion as well for the individual players too then?

Yes, exactly.