Products
Trends: Measures and displays popularity of search terms or Web sites. Launched in May 2006. The product was somewhat ignored for a while -- Google didn't update the data for months at a time, but now they're adding new features like Trends for Web sites, which lets you compare unique visitors for various Web sites.
Analytics: Detailed traffic statistics of your Web site, including AdWords performance tracking. From Urchin Software acquisition in April 2005, active. Google Analytics is used by about a third of the top 500 Web sites in the world, according to Pingdom, which measures the uptime of Web sites. It could face some competition from Yahoo, which bought rival IndexTools in April and says it's going to make the service free, like Google's.
Music Trends: Displayed the music that the users of GTalk most listened to in a "Week's Top Songs" list. launched in Summer 2006; Shut down March 2008.
Zeitgeist: A monthly and yearly summary of Google Trends, launched May 2007. Zeitgeist is a good summary of what search terms got the most attention in a given month or year, but other than that it's not immensely useful or important.
Acquisitions
Urchin Software: Web analytics, bought in March 2005, became Google Analytics.
Measure Map: Weblog software, bought in Feb. 2006, became Google Analytics.
Trendalyzer: Statistical software (Sweden), bought in March 2007, became Google Analytics.
