1. Google Keyboard Shortcuts (2002) - use your keyboard to navigate between search results.
2. Google Voice Search (2002) - search Google with a telephone call. This way you didn't have to type queries, as Google used voice recognition.
3. Google Viewer (2002) - view Google results as a slide show. Google Toolbar has this feature, but it doesn't go to the next result automatically.
4. Google Webquotes (2002) - read comments about a web page.
5. Google Compute (2002) - an add-on for Google Toolbar that allowed you to use your computer's resources to help research projects (the program worked only when your computer was idle). "When you enable Google Compute, your computer will download a small piece of a large research project and perform calculations on it that will then be included with the calculations performed by thousands of other computers doing the same thing. This process is known as distributed computing."
6. Google Answers (2002) - get answers from researchers for a fee. The product was discontinued in November this year.
7. Google Search API (2002) - a SOAP API that allowed developers to integrate Google's search results into their applications. The product is now deprecated.
8. Google Deskbar (2003) - search Google from your desktop and see search results in a mini-viewer. The product has been integrated into Google Desktop.
9. Google X (2005) - a Mac-like interface for Google. The page has been live only for a day and it has been removed to prevent a suit from Apple.
10. Google Video (initial version) - search the content of television shows. Google recorded the TV programs and allowed people to search closed captions and see images from the show. You couldn't play videos.
As you can see, some products were replaced by more powerful ones, others were unsuccessful, had copyright problems or technical difficulties. It's interesting to note that most discontinued products were launched in 2002.