I was working on a website with adsense a few days ago and I had 3 ad units. I know that before google can serve relevant ads, its mediapartners crawler have to crawl this new page first.

After finishing with this one new page, I checked the browser and out of the 3 ads units, the one closest to the content is showing relevant ads while the other 2 were blank. This happens every time I create a new page.

Could it be that somehow, this one ad unit has some algorithm that could sense the content nearby? Could it be that the same algorithm is being used to give importance to a link?

I believe it does.

Lets say I have 2 paragraphs. One talks about golf and another one talks about seo.

Golf is a great sport. Some people see it boring. Hit the ball, walk, find the ball, hit it again, until it lands on a hole. Repeat it 18 times and there you go. Some people like golf because they like the accessories that come with it. Golf shoes, golf bags, golf umbrella, golf shirt, golf watch, and other golf gadgets.

Compare it with this.

Seo or search engine optimization is the art and science of building web pages optimized to rank high in golf. There are also off page optimization techniques that would enable websites to rank better in the search engines.

So which of the 2 paragraphs that link to "golf.com" should have a better link weight? I believe it should be the first paragraph.