Nothing, but there is at least 1, 2, or 3 enemy Intel items on each campaign mission, 22 Enemy Intel items gets you an achievement that is worth 25 Gamerscore and if you get them all (For Xbox it's 45 items), you get an achievement that is 40 Gamerscore.
You receive a trophy, for your achievement! And one step closer, in achieving the platinum!
if you collect all of them it gives you cheats in the main campaign
Nothing
if your on about the career mode then you need to complete it and get all the Intel for the special ops mode to get 3 stars on all missions and i believe past level 15 on all levels and in multiplayer to prestige once and you get an extra 100% for ever other prestige you get
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.
you unlock cheats such as a bad year where enemies turn into tires when you shoot them on single player
you don't use the Intel for a specific purpose. if you collect half of the Intel in the game you will get an achievement. if you collect all of the Intel you get another achievement.
nothing you just get achievements but infinity ward said that they will do what they did on cod 4 modern warfare 1 and make cheats for when u collect them
just achivement.. and that's it :D
you get a trophy
when you collect all the rubberbands in bully i get the famous RUBBERBAND BALL
you get unlimited ammo
you get a trophy