I have been in the habit for a long time of having Opera tell me about the cookies a site tries to set. Do this long enough and you recognise profiling libraries, popular frameworks and platforms. You also get to see what sites think they have a right to set a bazillion cookies when they should be able to be satisfied with one. This is a bad trend, IMO. Even Google Analytics makes multiple attempts to set its multiple cookies*.
You also get to see noxious practices like sites that require cookies and fail when you don't accept them (like a certain US ISP that just redirects endlessly if the cookie isn't accepted). >:-( Precious few actually tell you what's wrong and that they require them, but I can't remember any in a long time that tell you why.
Who else tends to approve all the cookies a website requires?
Wade.
* I heard from Google itself that about 7% of users reject cookies. D'ya think that's a lot? :-)