Find My iPhone - When your iOS device has been located, it shows the remaining battery level, so you know if you’re going to lose track of it soon.
OS X - Option-click Sound icon in the menu bar to change sound output and/or input quickly.
OS X - Searching in System Preferences highlights the relevant sections. The more relevant the section, the brighter the light will be.
OS X - Adjust the volume in 1/4 increments with shift+alt+volume keys.
Tweetbot - When replying to a tweet, swipe down to see the original tweet and author.
/via Kevin S.
OS X - Finder prevents you from accidentally modifying the extension when renaming a file, but only for known file types.
iCal - Shows birthdays from Address Book with the person’s name and age.
/via Clemens Mayer
OS X - When saving new files, invalid characters are automatically replaced with dashes.
/via Mario Uher