OK.. Let me see if I get the question.. You wanta third party program that you can either run on your machine or have on this web page where you can look at it and see who is on the server, and if you want to play with who is on.. if so then you kick the kids in the butt and get on and play. Yes there is.
One: http://www.serverspy.net/site/gamelauncher/
It will allow Lep. to put a server watch thing on this web site and you can see who is on the server and you can then click a join server button on that page to load up steam and join the server. I have used this and find it very useful.
Two: http://www.codeproject.com/csharp/GameServerInfo.asp
I have not used this program so I am not sure how good/bad it is.
Three: http://games.softpedia.com/get/Tools/Server-Watch.shtml#
Someone I know said this was a good program. I dont know personally, so it is one you need to check out for yourself.
Someone else posted about HLSW, it is a great tool.. but it is used on your end and not used on a web page like this.
If you want a Chatter that also will give you info on Servers Give X-Fire a try.
http://www.xfire.com/xf/index.php
Now if your asking about Stats as LEP said, then I would recommend PhyscoStats. http://www.psychostats.com/
OH Here is a Link I just came across it has a bunch of links there with discriptions of what the programs/links are.. there maybe what your looking for there. http://www.planethalflife.com/commands/tools.shtml
I hope this helps.
[addsig]