Google Trends, a service Google started two years ago to track searched-for keywords, has unveiled a new tool for inquiring minds looking to find out more on any given site. Like tracking services Compete and Alexa which use tool bars to grab user data, Google Trends now lets you pop in specific domains and compare basic traffic information about any .com site (or .tv, .biz, .net, and so on) using nothing more than organic user searches.
Included are daily traffic numbers in users (sent from Google search), where in the world the users are coming from, and related sites that were either searched for or visited in that same session. All of this information is color coded, and up to five sites at a time can be pitted head-to-head, with bar graphs and charts for each.
The service marks a notable openness for Google, which is privy to keeping its data locked up tight. It also appears to not tap into the data dug up by its own site reporting tool Google Analytics, which is used in many sites across the Web. As Barry Schwartz over at SearchEngineLand notes, it's also a great way to figure out related keywords and searches from people visiting your site, and those of your competitors--which is more than you get from Google's own AdWord choosing tools. I regularly bother my colleague Rafe Needleman to help me dig up similar sites to something I'm writing about, but with this tool I'll be able to use the wisdom of the crowd to do it for me.
One of the more interesting uses for this is comparing sites with traffic that surges around product releases. In the screenshot below are sites that cover Apple. Despite the minor differences, you can clearly see huge surges at various points in the year. In practice, you can cross-reference this with product keywords (still using Google Trends) and the data magically lines up.