Thats just what i thought - why can't just everyone stop selling under 680 $ :-)
Funny thing is: Buyers could do the same and just stop buying above 30$. And then?
Price will stay high and buyer will buy bitcoins at high, if they need bitcoins.
LOL!
Why not?
Price will stay low and seller will sell bitcoins at low, if they need moniez.
And believe me there are way more desperate miners out there that need to pay their bills with BTCs as there are buyers who are in a desperate need of BTCs.