Four minutes of trading on Thursday was caused by too many sell orders that were placed as Market Orders...
Scottrade won't allow placing Market Orders on penny stocks, but TDA Ameritrade does...Fidelity does also, and I'm not sure about all of the other online brokers...
Add to that the bid on Level II at the open that day was almost empty of MM's with any size...Like the MM's knew what was about to happen...
re: Petar's comment that he "didn't own any shares"...