Yep - I was on Polo when it happened. A few hours after the 200+ BTC buy wall went, someone in the trollbox announced they were dumping. Price went from around .0006 to .0002 in less than 10 minutes. Wasn't much buy resistance at the time (4 BTC), so only took a 16k bbr dump to drop the price so dramatically. Price rallied straight away after that. Buy orders have been between 20-30 BTC ever since.
"someone" - quite the inventive user name for that polo user.
Well... when the price of a coin your invested in drops by two-thirds in a matter of minutes, it doesn't hurt to see who is saying what. Anyone who scrolled the trollbox at the time will know what was said and by whom.