I belive that WC is a bigger platform than the IPL. WC has more importance than the IPL.IPL is a league format whereas is a country specific.Every citizen wants his/her country to win the worldcup.This year the extravaganza has been doubled because the WC is happening in India,India is the most preferred country to win the WC and this may be Sachin's last WC.So,all this combined will make the WC is the most preferred platform than the IPL.Moreover,IPL happens every year but WC happens every 4 yrs.
So,considering the national audience WC is the best marketing platform.This is evident from the money been poured into the WC 2011.International audiences have a slightly diff taste than the local ones.Cricket doesn't have International fan following like Football.Cricket is a 8-9 hrs affair and most international ppl don't want to spend so much time before the screens watching the game.So,they would prefer the shorter version where the IPL can fit in.
-Deepak.