#5 Google Buzz

Google Buzz was a social networking, microblogging and messaging tool that was developed by Google and integrated into their web-based email program, Gmail. Users could share links, photos, videos, status messages and comments organized in "conversations" and visible in the user's inbox.

On October 14, 2011, Google announced that it would be discontinuing the service and that the existing content would be available in read-only mode. Buzz was discontinued on December 15, 2011.

#4 Google Notebook

Google Notebook was a free online application offered by Google that allowed users to save and organize clips of information while conducting research online. The browser-based tool permitted a user to write notes, clip text and images, and save links from pages during a browser session. The information was saved to an online "notebook" with sharing and collaboration features. Notebooks could be made "public", or visible to others, and also could be used to collaborate with a list of users, either publicly or privately.

The service was discontinued in September 2011, and Google launched a similar service, called Google Keep in March 2013.

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