It is a well known fact that Google has been making its way into uncharted territories. They started off with competing against the Office Suite and carried it on with a competitor to Paypal a online payment system.
Google Trends uses a variety of data to create the trends;
Google Trends Combines information from a variety of sources, such as aggregated Google search data, aggregated opt-in anonymous Google Analytics data, opt-in consumer panel data, and other third-party market research
The data in itself is vast and can be quite accurate given the reach of Google.
Check the screenshot below where we did a comparison between yahoo.com, microsoft.com and aol.com.
We also did the same comparison with Alexa and found quite similar results.
Google Trends also shows demographic data such as areas and similar visited sites along with the search terms that have brought traffic to the sites.
The features look good and we believe that the competition for trending has just arrived and only time will tell who will survive the battle. If you are looking to create your own trends go ahead and visit Google Site Trends.