2007 was probably the year when Google announced a lot of new innovations and Google started improving search. Few changes to Google's ad system were also done which is Google's main money-maker. But one thing which is not good for any company is relying too much on one thing to make the bucks like Google does with Adsense & Adwords. Thus, Google really needs other sources of revenue.
Internet market research is a good business these days. A few companies are already making it big like Alexa, Comscore, Compete, Inc, Nielsen//NetRatings, Hitwise, and Quantcast. And as online advertising increases, marketers would want to know more about the users. I think with the kind of data Google owns about web users, it could easily sell this as marketing data. Some people would argue that Google already gives some idea about the users through adwords, but that data is mostly from external sources. Data from gmail, orkut, analytics, adsense and other Google services would be more comprehensive and that would mean very accurate data. Accurate also in the sense that Adsense ads are shown everywhere on the net and users could be tracked easily across different sites. This would mean that no one will question the accuracy of the results shown through Google's vast data.
With Google acquiring DoubleClick and FTC clearing all the paperwork, it seems Google will know a lot about everyone. Thus in 2008, I think Google will find another revenue stream by providing data for Internet market research.