Is there any website (like Alexa, website outllook etc) that can give the number of unique visits to websites? - Yahoo! Answers

Is there any website (like Alexa, website outllook etc) that can give the number of unique visits to websites? - Yahoo! Answers: "Is there any website (like Alexa, website outllook etc) that can give the number of unique visits to websites?
Is there any website (like Alexa, website outllook etc) that can give the number of unique visits to websites?I dont need this to measure unique vistis to my website. I rather need it to compare different websites within a particular industry.
Would greatly appreciate help!Thanks! :)"