Here is search logs of 650,000 AOL users. It's very interesting to view search history of particular person and analyze his personality. Let's do it together! Read more about AOL search database scandal or view research papers on web searching.
don't judge a book by its cover
The very common English iiom "don't judge a book by its cover" is a metaphorical phrase which means "don't determine the worth of something based on its appearance". It is probably the most common expression used in English to convey this idea.