Google Adsense

So, you’ve got your blog / website, you’ve signed up for adsense, and you’re all ready to make money - but you keep getting weird, off-topic ads.

How Google Adsense Works

When you place adsense ads on your site, an automated software robot (called ‘mediapartners’) usually comes to look at the content of your new page within a few minutes. This content is then run through a rather complex algorithm. The algorithm looks at things like:-

* The textual content of your page.
* Keyword Density (ie, what words and phrases appear regularly on your page)
* What sites your page links to.
* Your pages header, and keywords in the url.

Once that’s been done, adsense tries to work out what your page is about, and then, according to Michael, it aims to display the ads that will maximise your income by a combination of these two factors:-

1. Presenting ads that are contextually relevant to the content of your page, and therefore likely to be clicked (called a high click through ratio, or CTR).
2. Presenting ads with the highest possible return per click (called effective Cost Per 1000 impressions, or eCPM).

When Adsense Gets it Wrong

Sometimes, however, adsense seems to get the whole show wrong. As an example, I recently wrote a story about getting pages out of Google’s supplemental index, in which I talked about ‘infant pages’.

Next time I looked, I had ads on that page about colic and baby products.

Does this mean that Google thinks my page is about infants? NO - the adsense robot is a completely seperate entity to the google indexing robot - and I don’t think it works quite as hard at times to work out the real context of a page.

So, probably what has happened is that the adsense robot has checked my whole page and figured out that serving ads for the keyword ‘infant’ would be great, because it is a lucrative keyword.

What’s a lucrative keyword? Well it’s like this - advertisers compete for keywords - in a kind of automated auction - so if I’m wanting to sell acme widgets, and I know I make $1000 per widget, I’m likely to pay more for ads to appear on pages with the keyword ‘widget’ than someone who sells less profitable ajax brand widgets.

It seems that ‘infant’ is probably a lucrative keyword, and in a perfect world, I’d get really high earnings from having ads about infants on my page.

That’s really clever, in a way, but really, it’s quite obvious to me as a human being that the technical types on my site are probably quite unlikely to be looking for baby products, so my CTR (number of clicks per 100 ‘views’) is going to be quite poor.

Adsense is a computer algorithm, not a human, so it’s ocassionally going to make slip-ups - that’s a given.

So, to get more contextually relevant ads on that page, I can either remove the keyword that’s confusing adsense, or I can use a relatively new tool from Adsense - enter, stage right, a little thing called Adsense Section Targeting.