What's going on here? Google Search for Tarsnap.
google.com
google.com
All I can say for certain is that somehow the Tarsnap index page disappeared from the Google index. (Googlebotbait: Please follow this link and re-index it: http://www.tarsnap.com/)
EDIT: It looks like the page is now back in the index, just not ranking highly for "tarsnap" -- a search for "tarsnap site:tarsnap.com" now finds it, which didn't happen yesterday.