The main concept behind the app is intelligently understanding the best time to remind you about a task. Think Google Now and Reminders in iOS 6/7.
The interface will be simple and uncluttered, but still powerful, with more complex features staying out of the way until required or used. One of the biggest issues with this app will be minimising the amount of time it takes to perform an action in the app -- so it should feel simple and comfortable.
I know the example logos I've provided are all very similar, but feel free to experiment and explore outside this limited style. The examples demonstrate the style of logo that I'm expecting to go with, but I'm not certain yet. This is just the style that I'm thinking at the moment.
I'll explain why I've selected each of these logos as examples:
Bluebox: The font (thin, clean, "o", "b", and "e" are consistent); words separated by colour
Last.fm: The "as" joined together (it's animated in the app when loading, used for the app icon)
Dropmark: Thin font and bright colour fits well with iOS7
Authy: Clean icon (adapted well for app icon); subtle two-colour effect (don't like the font/capitals though)
Snowbird: Alignment of the icon/text; animated when loading (http://snowbird.com, then click a link)
Rdio: Musical notes hidden in negative space; app icon is consistent
Dropbox: Icon is usable by itself (in some contexts) to identify the brand (don't like the font at all though)
Chrome: memorable icon; lowercase lettering (don't like the text colour though)
Orkut: circular "o" (could be used for "opportune"); "o" could be incorporated into a loading animation? (would prefer thinner font)
Amazon: "a to z" implication; is sometimes shortened to just "a" with the yellow arrow underneath
Some other things to consider:
* Ability to adapt the logo to be used in an app icon
* Potential to use part of the logo in a loading animation (e.g. last.fm and snowbird)
* Consideration of compatibility with existing design in iOS 7 (e.g. dropmark)
* Brand name in lowercase (unless capitalisation could help with a different item on this list?)