Here's something that came to me today while whizzing across the city on my Vespa. The basic idea is that you use Flickr to help students differentiate between similar words which can be easily confused if you just present them as a list in the lesson.
e.g. march, stroll, stride, trudge, wander etc
The students then search on Flickr for photos that best show the meaning of the word. They then use Slide.com to make a slide show to put on their class/ personal blog. Afterwards they look at other students' blogs to comment on their choice of photos.