It's a really simple website which you can bookmark and go back to whenever you want, to paste or jot down any random notes you might want to whilst browsing the web.
NotePlan - Make plans inside an individual markdown note for every day in your calendar. Use it as a journal for your daily tasks and plan todos in advance. For Mac, iPhone and iPad.
Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.
Mochi - Write notes and flashcards with Markdown and study them with spaced repetition.
A5 - Takes notes in your browser. Elegant & simple.
Inkdrop - The note-taking app with robust Markdown editor, supporting macOS, Windows, and Linux.
Chars - Unicode Symbols Keyboard for iOS