Originally posted by Regicidal
There are games that go
1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.e3 c5 5.Bd3 Nc6 6.Nf3 Bxc3ch 7.bxc3 d6 8.e4 e5 9.d5 Ne7 intending ...Ng6 and an eventual ...f5
This is my favourite line of the Nimzo, so I'll offer my 2 cents on this one. The point is to blockade the centre so that Black's two knights will stand better than white's two bishops. Obviously white will want to open up the centre in order to open lines for his bishops. Notice that Black has fixed his pawns on the dark squares (c5, d6, e5), so that his light-square bishop isn't impeded by his pawns. Hope that helps.
If you want an instructive game on this, see Spassky vs Fischer game 5, world championship 1972.