Google Image Labeler
Google Image Labeler is a new feature of Google Image Search that allows you to label random images to help improve the quality of Google's image search results.
You'll be randomly paired with a partner who's online and using the feature. Over a two-minute period, you and your partner will be shown the same set of images and asked to provide as many labels as possible to describe each image you see. When your label matches your partner's label, you'll earn points depending on how specific your label is. You'll be shown more images until time runs out. After time expires, you can explore the images you've seen and the websites where those images were found. And we'll show you the points you've earned throughout the session.
If you are interested in helping Google improve the relevance of image search results for users like yourself and you have some spare time then why not give it a go ?
Although you do not have to log in to your Google account to help, logging in will allow you to keep track of your points. You can also choose to provide a nickname, or you can remain anonymous.