When Bing (Microsoft) get hold of Yahoo, most of the ads will still be run by Yahoo and they'll get most of the revenue, according to a few news reports. But what does it mean for SEO for these search engines?

Do you now SEO for only one of the two combined search engines? And how do you know which one will carry the weight for search? if they are staying relatively separate for advertising revenue at least to start with, will they also keep their respective search algorithms?

SEO is not easy already. With billions of sites already developed, and sites being added every minute, SEO for a specific site is very time consuming, labor intensive, and expensive. Unless you are in an undiscovered niche, SEO is complex.

For now, SEO for yahoo and Bing appears to be what it has aready developed into.  Maybe their "ARIA" which is supposed to be launched in December, is their combined search.