StrikeApp.com. There have been a few questions asked about it on the FreeTech4Teachers Facebook page so to answer those questions I recorded the short video that you see embedded below.
Applications for Education
One of the things that I like about StrikeApp.com is that students don't have to register on the site in order to use it. They simply start creating lists and each list is assigned a URL that they can share with you, their parents, or their classmates.