It's been a couple of years now that Google has been in the contextual advertising game, serving up ads not just in the search results, but also across the network of AdSense publishers. AdSense has since become a dream come true for many small publishers realizing they can make some cash from their blogs and hobby websites.

But when it comes to the largest of the large sites on the web - nearly all of them rely on the DoubleClick ad server to serve up their media-based ads - everything from Macromedia Flash ads to interstatials (the between-page ads CNET is known for) to peel-downs. In fact, it wasn't too long ago when DoubleClick acquired a competing ad server technology, Falk AdSolutions.

So it's no wonder that, after realizing just how lucrative the Internet advertising game is, Google has shelled out 3.1 billion dollars for, not just the technology, but the instant access to exclusively rule the advertising on the vast majority of the web.

The timing is just right, too. It wasn't very long ago that Google expanded its bid-for-placement AdWords system from just text links to banner advertising, and, more recently, some Flash based ad creatives. DoubleClick will expand on the multimedia opportunities of the AdWords/AdSense system.

There's another piece of the puzzle though. DoubleClick has just recently launched a new product which is actually an online marketplace for interactive advertising - essentially something that unites advertiser with publisher but with more traditional forms of online advertising. Certainly something that could be seen to parallel Google's AdSense / AdWords system.

Buying out your competitor is one thing, but should these two companies truly merge, Google would have control of nearly all forms of advertising across the majority of the web. It is yet to be seen how data mining will come into play here ...