I'm hearing a lot of crap talked on the reasons for the rise including gox somehow manipulating the price up while having 850k of coins on their books that didn't exist (by that logic gold should be $50k an ounce by now). The price was being held down so when the trend was broken that tension was released and it went up with a bang.
The market data is very clear. Mt Gox manipulated the Bitcoin prices by a huge extent. At times, the spread between Mt Gox and Bitstamp exchange rates reached almost $100. ($1,100 - $1,000).