Tackk is a nice service for creating simple webpages, announcement pages, and digital portfolios. I wrote a review of the service back in April. Today, Tackk added a new feature called Stream.
At its core Tackk Stream is a commenting system. But these are not your typical text-based comments. Tackk Stream allows you to include videos and images including animated GIFs in your comments. Tackk Stream can be made private or public. In the announcement of the new feature the Tackk team suggests using Stream for collaborating on the creation of task lists. Of course, you could simply use the service to gather feedback on something that you've written on your Tackk page.
Tackk from Tackk on Vimeo.
Applications for Education
Tackk could be a good tool for students to use to quickly create a page to show off some of their digital photography, video creation projects, or audio files. If your students use the private option you could use Tackk Stream to give them feedback on elements of their digital portfolios.