If you're having an issue whereby the server browser and 'play now' buttons aren't bringing any servers up
Shut down Steam, go to your Steam folder and then delete the clientregistry.blob and then open User data, then find your user folder and delete the 440 folder in there.

Just cos a load of people seem to be having that (including me)
( Theoban What of it, Thu 30 Jun 2011, 11:14, archived)

Mine was on-off yesterday.
But It seems to be random.
( Tzarkahn is waiting for Christmas to come again, Thu 30 Jun 2011, 11:15, archived)

I find sometimes the 'play now' button is just slow to populate

( Theoban What of it, Thu 30 Jun 2011, 11:17, archived)

Looks like steam are lookign into it.
forums.steampowered.com/forums/showpost.php?p=23197038&postcount=61
( Tzarkahn is waiting for Christmas to come again, Thu 30 Jun 2011, 11:18, archived)