Mammoth is described as 'Curation + Collaboration' and is a Note-taking Tool in the Office & Productivity category. There are five alternatives to Mammoth for a variety of platforms, including Windows, iPhone, iPad, Android Tablet and Online / Web-based. The best alternative is Notezilla. It's not free, so if you're looking for a free alternative, you could try Permanent clipboard or Vov Sticky Notes. Other great apps like Mammoth are Team-One (Paid) and Creonomy Board (Paid).
Notezilla is the leading sticky notes app for Windows, Android, iPhone/iPad and the web. Set reminders to sticky notes, Pin sticky notes, attach them to websites, docs & folders, sync between PCs and other devices, organize using folders and tags.
For many people, the desktop is simply the place where shortcuts and icons are located, without any real functionality. Nonetheless, you can benefit from all the empty space on your desktop by adding post-its, and Vov Sticky Notes is one of the apps that can help you do that.