Google AdSense and similar advertising networks rely on the context of pages to deliver the best-performing ads. Keywords create the foundation of the context.

That’s why the ad type is called, not surprisingly, contextual advertising.

The context of the page is formed by the major elements of that page – all related to search engine optimization. The starting point for the optimization of the page lies with the keywords found on it, including:

1. Document title
2. Document meta description
3. url of the page or site

Note that all three of these elements appear in search engine result pages. In addition, these factors improve the optimization of the page:

1. Headline of the article
2. Body of the article
3. Alt tag of the photo

Look at a page on a site that has Google AdSense. Are the ads that appear related to the content of the page? If so, do the keywords that appear in the ad also appear in the elements listed above?

The addition of a single relevant sentence to a page – or even a few words added to the meta description -- has sometimes been enough to improve the relevancy of the ads appearing on that page.

An effective tactic for increasing contextual ad revenue is a site audit. Check each page to see if it is getting the most relevant advertising. If not, example the document structure to find out if keywords are missing.

Once the keywords are added, it may take some time before the page is updated in the search engine index for more relevant ads start appearing. Some pages will improve within days, others within weeks or possibly longer.

An audit will increase the click rate and revenue per click, resulting in higher effective page CPM.