What do the intels in mw2 do?

If you get all the Intel in Call of Duty: Modern Warefare 2, nothing happens. However, you can gain achievements for collecting them.

Joshua's Improved Answer: Actually the enemy Intel you collect earns you cheats for single player campaign but first you need to finish the Campaign first to use the cheats.

P.s. I sometimes misspell Warfare from Warefare also.