To connect to a server running on steam, going into the browser type "steam://connect/IP" IP being the server IP (and port). In one banner where you can click to join, it says it requires GT lite, but with this simple method, you don't.

Hi mitterdoo,

Yes, that is a way to join a server through steam. You can find more information on the steam protocol on https://developer.valvesoftware.com/wiki/Steam_browser_protocol

GameTracker uses the GT Lite client so that user's can track their game time on their profile, manage their favorite servers directly in the client, be more flexible and user-friendly with command line args, and so on.