Yahoo Inc. (NASDAQ: YHOO) will soon be selling display advertising and even video advertising on the website of the world's largest retailer, www.walmart.com. The companies announced the partnership Wednesday, although terms of the multi-year deal weren't announced.

Wal-Mart Stores, Inc. (NYSE: WMT) indicated that advertisers would be able to buy ad space alongside walmart.com's product and information pages, which brings up the question: will Wal-Mart allow competitive ads to sit alongside its website pages? Display ads are graphic ads, unlike most Google Inc. (NASDAQ: GOOG) ads that are text based.

Imagine this: a customer is looking at a Black & Decker weed trimmer at walmart.com and a full display ad from Target Corp. (NYSE: TGT) or The Home Depot (NYSE: HD) pops up with a competitive model and a link to where it can be purchased. This scenario sounds like it could easily happen here.

It will be quite interesting to see how this partnership is launched and how Yahoo!'s display ads are implemented into walmart.com's website -- and if any advertiser can buy ad space on one of the largest e-commerce sites on the web. Perhaps Yahoo! will financially make it worth Walmart.com's while.