Made by the company behind WordPress, Simplenote is an easy way to keep notes, lists, ideas, and more. Your notes stay updated across all your devices. No buttons to press. It just works. Your notes are synced across your devices when you create, add to or change them. Registration is required but the app and service are free.
- Simplenote is much less functional than Zim (no rich-text, no attachment to notes) and although it does work on mobile, it syncs your data via web-facing servers on which your info is held unencrypted. In that respect your information is much more vulnerable to hackers and govt agencies than if you used Zim, stored the data locally and maybe - if you need - sync it with an end-to-end encrypted service like Spideroak, Tresorit or Seafile (Seafile encrypts file content, not metadata).
- Free and free of problems. Just simple.