superclown2 - 11:54 am on Oct 1, 2011 (gmt 0)

how do I find what they were looking at? How do I know what came from them?

Look through your logs for a visit from Google's IP range, probably beginning 66.249. Check whether it's a live visit or a bot, their bots look for robots.txt and their browser is googlebot. Live visitors (at least the ones that I have tracked) browse with Macintoshes.