in news: Hackers turn to Google
 

COMPUTER hackers have adopted a startling strategy in their attempts to break into websites. By using the popular search engine Google, they don't have to visit a site to plan an attack. Instead, they can get all the information they need from Google's cached versions of web pages, say experts in the US.

full story

i should check my sites for backdoors
i usually lack security :(

Google hotlinks the images. Put an invisible img src on every page of your site that logs referer lines from search engine queries.

hmm, that's why im getting some backdoor visits from google.