Online Advertising

I noticed today that wal-mart has begun to advertise on large webistes such as Yahoo.com, etc. I thought this was interesting because I am used to seeing online ads for other online companies, and wal-mart is obviously a very large retail company. But, now their online business is growing and they are actually earning a lot of money through online sales. Clicking on their online ads actually takes you to Wal-mart.com which is made, not to advertise for the store, but to serve as the store itself.