I just love this post that Gen did at North Coast Gardening about horticultural uses of the new Google "search by image" feature. It searches based on an image, not on words, by sifting through other images to find similarities. It's interesting when it works, but even more interesting when it doesn't work. Look what a search for an orange carex turned up:
Brilliant. Go over there and read the whole post–it's terrific.