It is fun to use Flickr to find pictures that people post for others to use. Or use FlickR to post your own albums. Here's a site (Spell with Flickr - http://metaatem.net/words/) where you can have any word spelled with different pictures that have each letter in the word.
Erik Kastner used the letters from the One Letter group with the Flickr API and is making the Source Code available for free.
Bookgoo allows you to highlight and annotate your documents in the same way you would mark up a piece of paper with a highlighter and pen!
Get started with bookgoo in 3 easy steps:
STEP 1 - Upload your content
STEP 2 - Highlight and annotate your document
STEP 3 - Share your document with others
Montage-a-google is a simple web-based app that uses Google's image search to generate a large gridded montage of images based on keywords (search terms) entered by the user. Not only an interesting way of browsing the net, it can also be used to create desktop pictures or even posters