Answers.com extension for Firefox takes any word you highlight and provides a quick pop-up with a definition of what you highlighted.
After installation of the extension and restart of Firefox, Answers.com worked just as it should. While I was writing this, I tested Answers.com to see how up-to-date it was and highlighting the word "blogosphere." Just as I expected, it quickly provided me with the correct definition.
To start using Answers.com, hold down the left Alt key and start highlighting a word. As soon as you release the mouse button, you will see the Answers.com pop-up window with the complete definition.
The Answers.com extension is extremely useful for people just starting in the computer industry. With all of the acronyms in this industry, who can keep track? However, if you are using Firefox, there is a search engine for Dictionary.com where you can type in a word and find out the meaning in a new browser window. The Answers.com extension provides the same functionality without interrupting your work which I'm thankful for. If you want Answers.com to go to a full browser window, you can make that change in the settings.
The rating for this extension is definitely a 5/5 because of its simplicity, usability, and unobstructive nature of the extension. It displays what you need to know and disappears so you can move on to more important things, like surfing the web. :-)