I just read about this interesting fact and had to pass it on.
Google indexes around 80% of them and Bing indexes around 30% of them.
Why? Obviously, Bing is pickier about what content it will index than Google. Bing trusts fewer links than Google.
That brings up a tremendous difference in strategies between attracting traffic for the different search engine audiences.
What works for Google may not be the best thing for Bing. Oh, and in case you haven’t heard…. Bing and Yahoo, pretty much the same thing these days.