Someone has mentioned here before about searching for "search engine" and "search engines" (without quotes) in Google and look at the result. I just did that and the funny thing is that Google.com doesn't even show up. Google.co.uk shows up on second page and even altavista is on the first page.
I guess people don't go to Google to search for search engines but you would think that with a PR of 10 you would be at the top?
It's kind of interesting and I don't think that they are "shy" and want to be nice to other SE's. Is there something in their algo that doesn't place them at the top of the results? Maybe a lot of people put google links in "bad neighborhoods" so they lost ranking? Maybe they just don't rank for "search engine" and never had.
Searching for Google brings up Google on the first spot and then wikipedia...
Another thing I have noticed is that Google doesn't seem to use keywords nor description tags!
Wonder how big their sitemap.xml file is?