An oft forgotten piece of search engine marketing is that every engine uses a different algorithm, which produces significantly different results. Getting an accurate view of your standing in the search rankings means visiting all the major engines - from someone else's computer so search history does not skew the results - and seeing where you are in each. Many companies choose to focus on a single engine, as SEO is already difficult enough, but getting the full view can be useful.
Yometa is a new web application that gives a more realistic view of search engine results. It shows the top results from the three biggest search engines (Yahoo, Google, and Bing), and generates a Venn Diagram that shows if a given site is on one, two, or all three engines.
The company's blog points out that typically only 3% of search results overlap. For example, entering "concrete" generates only three pages in the center: Wikipedia, ACI, and Concrete Network's concrete calculator.
Entering "construction" finds no sites common to all three:
Even powerhouses like Wikipedia are not always in the center; entering "Microsoft" finds their customer support and download center, but not the company's homepage or Wikipedia entry. "President Obama" only found one page on all three sites, and it's not the White House.
Now the good news is that even though we're talking about the "three biggest search engines", #2 and 3 combined get about 1/10 as much traffic as Google, so single-engine optimization is not leaving too much on the table.