It's been several days in a row that I go to dustcoin and see Dogecoin being listed as less profitable than either Digitalcoin and BBQcoin, with the latest being the most profitable.
But then if I go to coinwarz I see the inverse: Dogecoin is the most profitable, next Digital and finally BBQ.
The prices listed for them are not that different, nor is the difficulty - below the values. E.g. the values at the time of writing this question - first columns are from coinwarz and then the values for dustcoin:
coin vs. BTC diff. vs. BTC diff. BBQ 0.000048 (Cryptsy) 4.3986 0.00005165 3.192 DGC 0.00036494 (Cryptsy) 11.3679 0.00035000 8.062 DOGE 0.00000031 (Coins-E) 286.6240 0.00000028 271.845
I would've thought that getting the profitability would be a straight away calculation, given the hashpower at your disposal vs. the avg. reward for a coin, plus the difficulty of it's network and the value it commands on the market.
So I can't explain why each site gives the exact opposite answer for these coins in particular - my inner cynic suggests at least one of them gets paid to artificially increase/decrease the profitability of some coins, but I find that hard to accept as well.