Notice in the list you posted, the best bid (highest bid) is 0.006 by HDSN and the best ask (lowest ask) is 0.0069 by PERT.

But ScotTrade is still showing the best bid as 0.006 (happens to be same as HDSN is now) and the best ask as 0.0062. So you can easily go in and get shares at 0.0062, and not have to pay 0.0069.

There is an invisible MM out there!