Google gives users access to search data.

This has been a busy day for Google. In addition to Google Co-op and a new version of Google Desktop Search, the company has also launched a test version of Google Trends.

In essence this search tool gives you information on how popular a specific topic (or — rather — a specific query) is among Google searchers. You can enter up to five topics and see how often they’ve been searched for on Google over time.

In Google’s words Google Trends “analyzes a portion of Google web searches to compute how many searches have been done for the terms you enter relative to the total number of searches done on Google over time.” Google then shows you a graph with the results.

Google Trends will also tell you how frequently a topic has appeared in news stories featured by Google News and how this popularity varies in different parts of the world.

“For the first time ever, Google is making it possible to sift through billions of search queries from around the world to see what people are thinking about,” says Marissa Mayer, Google vice president of Search Products and User Experience.

Google Trends will also be useful for search engine marketing experst trying to find out what users really are searching for.

Google Labs are also testing a new notebook service: Google Notebook lets users clip text, images, and links from the pages they’re browsing, save them to an online “notebook” that is accessible from any computer, and share them with others. (The link is not working at the time of writing)