This is not something that will happen over night. You meant to say that Gazprom was the most profitable in 2009.
Exxon did $30B profit in 2010. - http://www.google.com/finance?q=NYSE:XOM&fstype=ii
Exxon did $30B profit on $375B revenues. Net profit margins of less than 10%.
Of course we won't know until Dropbox releases their financials, but I strongly believe that they will be a bombshell when they are released. Nothing like anything we have ever witnessed.
I would not be surprised if their Net Profit margins are 30% - 50%.
At those rates, all it takes is for them to be doing revenues of $100B to exceed Exxon's profit take in 2010.
I know it seems a bit far fetched now, but so did every other technology giant when they were in the budding phases.
I think it would be foolhardy to bet against them.