Why am I seeing this logo already on a official twitter, FB page and quarkcoin.cc? Am I missing something?
You're not. It's very close to the original logo, which everyone likes and still uses (which is what you're seeing on those sites).
In my opinion, this contest will fizzle out because it's too late to change the Quark logo now. It either had to be done very early after launch, or MUCH later down the road when the brand has its own legs and doesn't rely on the logo as much. Right now, changing the logo will only confuse people.
But that's just my 2 cents.