At Google we're great supporters of experimentation because it's only by trying new things (even if some of them don't work out) that you discover better, more creative ways to operate. We've been testing different advertising formats for years (some have been more successful than others), and over the next few months, you'll see us continuing to experiment with new ads in new places.
If you're based in the U.S. you may already have spotted or clicked on the different text and image ads we’re testing on the results pages of Google Image Search. And last week you may have noticed we launched Sponsored Videos on YouTube — a great example of matching ads to content.
In addition, we are today launching text ads on Google Finance in the United States. We're also looking at how best to show display ads on Google Finance. And later, in the very near future, we will start testing text ads on a small number of news refinements within Google Search — so if, for example, you type "iPod" into Google.com and then click on the news link on the upper left-hand side, you might see text ads alongside those results.
Whenever we make changes like these, we carefully evaluate users' reactions to ensure we're holding true to our basic principles: that ads by Google should always be relevant and useful. Of course, these experiments benefit Google because they generate revenue from new sources — but by ensuring that we show the right ads at the right time to the right people, we'll add value for users too.