how can I know the audience of a web site

[zizoubar]

How can I know the audience of a website ?

[bsjut]

You can use, for example:

• Doubleclick Adplanner: http://www.google.com/adplanner/
• Alexa: http://www.alexa.com
• Compete: http://www.compete.com (Paid Service)
  
• Hitwise: http://hitwise.com (paid service)
  
• Nielsen Netratings: http://nielsen.com (paid service)