I signed up with Diigo.com last year. Diigo is a social bookmarking site, very similar to Delicious. Both sites allow you to take the bookmarks that you would normally create in Explorer or Firefox and easily post them on a public website so that you can share them with other people. These are very handy sites for teachers (especially those who don’t know how to create a website) because they both allow you to setup a collection of links for a research assignment and then send your students to just one URL where all your sites are listed.
In other words, instead of separately writing down the websites and their URLs for my assignment on Sir John A Macdonald, and having the kids punch them into their browsers (and make lots of errors in the process) I can simply give them my Deliious link http://delicious.com/mrpuffin/sirjohna which has all the various sites listed.
Social bookmarking is handy on its own, but Diigo allows you to share bookmarks in a cool way. A group of people (students in my case) can share a common area to post their bookmarks. They can edit each other’s work and leave comments for each other.
This is really very cool for students collaborating on research projects. Yesterday I had students researching historical Canadian human rights issues pool their bookmarks in a Diigo group so they could each use the best of the material that the others had found. The login of the person who posted the link is put beside the posted link so you, as teacher, can easily see who’s contributing and who’s not. It’s quite easy to hold people accountable.
You also have an ability to edit most things. I haven’t checked out everything yet, but I think you can edit almost anything potentially offensive that your students could post.
There is an educator version of Diigo, as well, which allows you to create users (without them having to submit e-mail addresses) and create groups for your users to work in. Understandably, that’s incredibly useful in a classroom setting.
The only downside I’ve seen so far was the length of time it took Diigo to process my application for an educator account. I first applied last May and it seems to have been approved last week. Admittedly, all of this service is free (including the education upgrade) so I can’t really complain, but with the lagtime involved I wouldn’t plan on using Diigo really soon after you apply for it.