Are you being targetted?
Since Google adwords introduced site targetting I've been very conscious as both a publisher and advertiser of the possibilities of what this meant. However it wasn't very easy to see whether ads were being sent purely based on keywords or the actual url itself.
The adsense blog provides a handy tip for adsense publishers to work out what percentage of the ads is site targetted and what is contextual.
Unfortunately they still aren't telling you which advertisers are using which method.........
| 
Very interesting. I did not know about this. So contextual means random ads and Site means ads especially targeted to your site? That’s what I think anyway.
Cris - basically yes.
Contextual is based purely on the content targetting ie. keywords and phrases while the site targetting means that the advertiser has chosen your site(s) for their ads