So yeah, we've been thinking of adding our servers to gametracker for a while now but haven't done so since they are non-steam, but yet most of the Left 4 Dead servers listed and ranked are almost all non-steam.

So is that allowed or what?

While we greatly discourage illegal activities, we don't yet have anything in place to detect and block them. However, if the page directly contains any illegal content, like links to download pirated games, the server and page owner will be blocked.

Ok thanks for th info. But I'm surprised you don't have anything in effect to detect and block them. I mean many of them have no-steam right in their title. Also for the server variable sv_tags almost all of them use no-steam or nosteam or nonsteam. Another server variable which is a sure fire way to tell is if it's not running the current version of the game which is available on steam (if it's more than one version number behind it's definitely a non-steam server).