Collaborative, embeddable, interactive timelines with TimeRime … you can even set up your very own school timeline environment for a modest outlay.
Keep a record of, and share what you thought about the books you and your students have read … and learn what others thought using LibraryThing.
Simple online video editing, collaboration and sharing using Pixorial.
Bring together collections of images, then annotate or comment on them as a group using Marqueed.
Bottlenose might help you turn all those data streams and sources into a manageable supply of meaningful information.
A world wide map of photos, Panoramio users upload photos and locate them on a Google map. You and your students can explore and/or contribute.