Google is really dedicated, I can't imagine how many people they have to be able to do this:
Google is currently blocked from crawling your site by the robots.txt file that your server uses to control access by search engines. As a result, users who are looking for your site are not able to find it using Google. As you know, a large fraction of internet users use Google as their starting point and over 50% of search engines referrals come from Google. Google's mission is to deliver the best search experience on the Internet by making the world's information universally accessible and useful. We would like to include your site at http://lishost.org in Google's index to make it easier for your users or customers to find your site.
I got that from the LISHost form, and I don't think it was sent by a bot, but rather a real live person. It's no wonder they're #1, and saying over 50% seems to me modest, I'd say more like 80%