Exxon Mobil is big, but Wal-mart is bigger than any of the private oil companies. There is nothing wrong with making a profit from their industries.

Exxon Mobil 2006 Financial Statement

Revenue- 49 billion
Return on capital- 33 percent
Capital expenditures- 756 million, with plans ongoing for a petrochemical plants in Qatar and Saudi Arabia, as well as a petrochemical complex in Singapore.

Total revenue- 377,365 million
Total costs- 310,000 million
Income taxes- 28 millions (Sales-based taxes included in costs)
Net Income- 39 millions.

Not too bad an annual report; should satisfy most of the many shareholders, large and small, including pension funds.
Ends up at $6.62 net income per common share.
(Share price about $87.00).