Padlet (formerly called Wallwisher) is a shared virtual space which can be used and shared in a variety of ways (moodle, blog, e-mail, facebook, twitter, etc.). Accounts are not necessary, but it helps to get a free account if you want more control over the site and use it frequently.
It’s been around for several years now, and it has been very robust. I use it a lot, especially for brainstorming activities, for microblogging, as an icebreaker, and a quick way to share links, images, or information. It works on pretty much any device: computer, tablet, smartphone, etc. It’s also a great tool for workshops because nobody needs an account, and the visual of the cork board means that everyone gets the idea of the tool instantly, explanations not necessary. The only downside is that if a lot of people work on it simultaneously, the arrangement of the individual items can get a bit unorganized. But that is really only a minor complaint.
For me, it’s one of those tools that I keep coming back to. This semester, it has been especially helpful in my advanced writing seminar.
Here’s a test site: double-click anywhere and try it out right now: http://padlet.com/wall/languagecenter