Wakelet is free bookmarking and note-taking service that I've been using since April when I started looking for alternatives to Padlet. On Wakelet you can create collection and sub-collections of notes, bookmarks, and pictures. You can add those materials to your Wakelet collections through a browser extension or by adding them directly to your collection on the Wakelet website.
Wakelet has always let users share their collections with others. This week Wakelet added the option to let other users make copies of collections that you make publicly available. Those who make copies of your collections can then add to those collections within their own Wakelet accounts. Watch this video to see how that is done.
Applications for Education
Wakelet's new "copy collections" feature could be used by teachers to start a small collection of resources for students to build upon. For example, I might start a small collection of resources for about a unit on my US History curriculum then have my students add their related resources that they find as conduct their own research.