The deal about Google MediaBot.
MediaBot (also known as Mediapartners-Google/2.1 ) is the Google crawler for AdSense publishers. What it does, is it indexes the pages which contain Google AdSense ads. Now since AdSense and AdWords are the bloodline of Google, webpages gets indexed more frequently by mediabot than googlebot. So that Google and the Publisher can show the most relevant ads and hence earn more money. This however did not help you in search engine rankings (claimed by Google).
But one thing changed few weeks back, Google search engine started showings web pages fetched by mediabot (which have not been fetched by googlebot).
Then Matt Cutts confirmed that indeed Google search engine will be showing results from mediabot.
Previously the configuration looked like this:
Now the configuration look like this:
What used to happen was that multiple bot would fetch a single webpage multiple time which lead to waste of CPU and bandwidth resources.
Now Google has a giant mirror of the Internet called cache. Your website is synchronized with the cache by the highest priority bot. The rest of the bot gets the content from the cache not from your website.
Matt Cutts from Google claims that your website does not get any advantage by using AdSense.
But I don’t agree with him. If you put AdSense on your website, mediabot will visit your website. So in practice, since mediabot indexes frequently because it’s related to the bloodline of Google, your website will be indexed faster and more frequently if you put AdSense. Now that does not mean you will get better ranking. But lets say you write an article about some rare new xummmmbuuu widget and you have AdSense on the webpage. Your competitor writes about the same widget but does not have AdSense on his webpage. Lets also assume there are not lot of webpages about the rare widget. Who will have better rank? You will. Your website will get indexed faster and hence get authority.
Remember you heard it here first, about this Google Hack. Now make some money.