Evernote is a note taking application which keeps the notes taken in sync across all platforms using its cloud infrastructure.

OmniFocus is a personal task manager.

GNotes is a simple and clear note app. It is available for you to take notes, keep a diary, write down ideas, create checklists, etc.

NoteLedge note-taking and management solution.

WizNote is a cross-platform cloud based note-taking client.

Penzu is a private online diary-hosting website.