internetheaven - 7:13 pm on Feb 22, 2013 (gmt 0)
I was chatting to a friend about this who had a phone conversation with an Adsense person a couple of weeks ago. Apparently he told her that it has changed and is now based on your browsing history/cookies? instead of keywords on the page.
That's not new. That's been happening for a long time. You can check what's being shown in the stats area. It will tell you how many ads were shown based on "Interests" (i.e. cookies) and how many were "Contextual" (i.e. about the stuff actually on the website).