I would think the reason Valve declined Vgchartz was that this site is pretty much a console website with hundreds of fanboys saying "PC Gaming is dead" without even being punished.
Hell, if it weren't for my insistence (and others) people here would keep counting games like Mass Effect as exclusives, ignoring the PC version entirely.
And there's pretty much no Top News of PC Gaming here. We get the random weekly Steam news and nothing else(plus news for other Steam deals).