I don't think anything miraculous is happening here. Google has devalued Wikipedia's links across the whole board in general.
This might be the reason that they are now higher in the big G: :D
[Check the advertisement, not the other crap :D ]
Paying for clicks in AdWords wont affect your SE rankings.
No, it will effect it.
If you leave your ads on there long enough, Google will actually index the ads.
google_ad_client = "pub-0123456789012345";
google_ad_width = 336;
google_ad_height = 280;
google_ad_format = "336x280_as";
google_ad_type = "text_image";
google_color_border = "FFFFFF";
google_color_bg = "FFFFFF";
google_color_link = "0000FF";
google_color_text = "666666";
google_color_url = "23383e";
That source code is execute by your web browser. Google (etc...) doesn't index what is in your web browser, only what is in the web server.