Today, in Malaysia, the Dell's advertisement is selling AMD-based product.
Surprised! :)

Not really. It was inevitable.

If looking at Marketing, you could work out that staying in a single product line would lessen a companies overall marketshare. Especially if that market was more inclined towards "cheap" home computers.

There is also the factor that if a Company sells a product that is madeup of subcomponents they only source from one other company, that "source" company sets the price of those subcomponents and the company selling has to pay that amount to use those components.

To keep the subcomponents cost down it's a good marketing strategy to cover more than one product line so as to generate a competative pricing scheme for subcomponents.