Drafts is the starting place for anything you might tap out on your iPhone or iPad, integrated with a large and growing number of other apps. This is a notebook that works like an Alfred-style launcher, and as with launchers, the more time you spend with Drafts, the more uses you'll find for it. Launch Drafts and type something — then tweet it, post it to Facebook, send it as an email, or add it to your calendar or Reminders app all from the same place. It can be saved to Dropbox or Evernote, or sent to to-do managers like OmniFocus, Things, and Clear. Custom URL schemes let Drafts integrate with still more apps; I use one to send new events to Fantastical.
A recent 3.0 update adds powerful new management features, including new archive and favoriting options for your notes, and a way to separate your most-used actions into tabs. It also brings tighter integration with Evernote, letting you set up templates for new notes with pre-filled notebook and tag information. If you jot down notes only occasionally, and use stock system apps for most of your needs, Drafts is probably overkill. But if you want to put your text notes to work for you, Drafts is an excellent place to start.