Publicnote is described as 'super-simple, free, public notepad. Enter any title to access a note. No account required' and is an app in the Office & Productivity category. There are more than 100 alternatives to Publicnote for a variety of platforms, including Windows, Mac, Android, Online / Web-based and iPhone. The best alternative is Joplin, which is both free and Open Source. Other great apps like Publicnote are Obsidian (Free Personal), Standard Notes (Freemium, Open Source), Google Keep (Free) and Microsoft OneNote (Freemium).
Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.