Google continues to prioritize (close and merge) it's product line as revealed on the recent earnings call. First came Google Labs, then the Slide product suite, and now they announced that many other products, listed below, will fade away. Google has said that with these changes "...we can devote more resources to high impact products".
(All bold product links direct to the product pages as of this writing; they will surely redirect to new locations in coming months. Screenshots have also been taken for posterity; click to enlarge.)
Aardvark: Closing September 30, 2011. Aardvark is a Q&A site that was acquired by Google in February 2010. I enjoyed answering questions from time to time and found the quality of questions mostly high and the small amount of spam questions was a joy. Of course, much of that has to do with the low volume. With the likes of Quora, Yahoo! Answers, and Ask.com (recently redesigned) it is a difficult field to compete in. Just Google your question! If you would like your data before the official closing just email firstname.lastname@example.org.
Desktop: Closing September 14, 2011. Google Desktop is closing down the product, including all the associated APIs, services, plugins, gadgets and support. With ChromeOS being the future, a desktop application is not needed.
Fast Flip: Closing September 6, 2011. Fast Flip will be closing along with the Google News version. It was essentially a way to flip through articles on various webpages in magazine style way. I did not use it much as the sources were limited.
Google Maps API for Flash: Depreciated September 2, 2011. The Google Maps API for Flash was launched to provide ActionScript developers a way to integrate Google Maps into their applications. Support will remain for existing Google Maps API Premier customers using the Google Maps API for Flash.
Google Pack: Closed September 2, 2011. "Google Pack was introduced in 2005 to make it easy to download and install a package of Google and third-party applications that helped users get the most out of their computers. Google Pack was responsible for fueling 100s of millions of software downloads. A lot has changed in the last six years. Virtually all new applications and services are now on the web. With declining interest in downloadable software, the time has come to discontinue Google Pack."
Google Web Security: Closed September 2, 2011. Google Web Security came to Google as part of the Postini acquisition in 2007. Much of the web security functionality has already been integrated into Google products, such as safe browsing in Chrome. Existing customers will continue to be supported.
Image Labeler: Closing Septemebr 16, 2011. Google Image Labeler was a game to help people explore and label the images on the web.
Notebook: Closing September 2011. Google Notebook was a simple way to take notes to share or publish on the web. All notes will be automatically exported to Google Docs upon closure. There is no longer much need for this service considering you can do this with Google Docs and also use many other services like Evernote.
Sidewiki: Closing 2011. I will miss Sidewiki! The Chrome extension has proved very useful to me to allow my entire browsing history to be saved to Google for later searching. It is also used in Google's Help sections as a built in way to comment; I even though it could be used as a commenting system. Although this one is closing in current form I fully expect it to live on in some way.
Subscribed Links: Closing September 15, 2011. Subscribed Links let developers and others create specialized search results that were incorporated in the normal Google search results for certain searches.