Hi Cratima,
I don't know if Yahoo if w3c friendly and I said it before somewhere that I don't actually care about MSN or Yahoo at all. I.e I'm monitoring statistics on 10 web sites and never saw traffic from yahoo or msn. Some web sites are purely USA based and appear on 1-5 positions among 1 -22 millions, so naturally you should expect much greater traffic from yahoo or msn, but it's not so.
So, I would say focus on Google and all other engines will pick up your web site as well, especially MSN, they are eating everything they find on the internet.
That's my opinion
