I am aware of this situation as another stock I hold was affected by this.
However, CPOW actually went to the pinks in Sept 2010. This was before the 600-odd companies were dropped by the market makers.
I do not have the story on why CPOW went from OTC to Pinks but I figure it has something to do with the reverse merger with General Bio Energy. CPOW was basically a solar/wind energy company before the reverse merger as near as I can tell. The company's whole direction changed in the reverse merger and a new prospectus wasn't issued until December.
Someone could poke around more on this subject if they want to.