memordo - Spaced repetition tool to help you retain more knowledge

SmartCards+ - Spaced Repetition Software for iOS. Modern, powerful and easy to use.

X (Twitter) - Connect with your friends and other fascinating people. Get in-the-moment updates on the things that interest you. And watch events unfold, in real time, from every angle.

Harken - Flashcard app using smart repetition to improve your memory

ScheduleTweet - Schedule tweets for when they will have the most impact

Yak Tack - remember. words.