This is only because of security issues on mtgox.
If you go to btc-e, they're still holding at roughly $600 I believe.
I'm basically done with dogecoin. The 1.5 rollout was a fiasco, there was no reason for the 1.4 fork, the lead developer has made and will probably continue to make terrible decisions, everything based on the bitcoin codebase is terminally ill, the dogecoin "community" is now represented by idiot-kings who don't understand the technology or markets, and I don't trust any of the exchanges at all.
In terms of speculation, particularly in light of all the hoops you have to jump through to turn real money into cryptos, you're better off playing with real derivatives written against real markets on real, audited trading platforms instead of assuming the crypto "exchanges" that haven't pulled a MtGox or GBL yet aren't in the business of pissing on your leg and saying "it's raining, we're investigating it" on Twitter.