Similarly to what Alexa.com has been offering with its traffic graph, Google has adapted the Google Trends service to show statistics about websites, aside from search queries.

Similarly to when viewing search query statistics, you can compare one or more websites by separating their URL with a comma. Only the websites that receive a significant amount of traffic are being shown, and in order to see the numbers that make up the graphs, you will have to sign in into your Google account.

Google explained that it is not showing the trends for most of its own websites because it can lead to investors making decisions based on those numbers, thus a conflict of interest.

The sources that Google is using to gather these statistics and compile them into graphs are still unknown. It is suspected though, that the Google Toolbar plays a role, the search results, anonymous Google Analytics information and market research.