Mac OS X Mountain Lion Spotlight - Finds Calendar & Contacts even when you type in their old names (iCal & Address Book) from previous versions of Mac OS X.
CSSHat - After purchasing and downloading CSS Hat, it adresses you by your email in the installation process.
/via Jonathan Shariat
iCloud.com - Removes the spaces from the email input field when you go to the password field.
/via Andrey Usoltsev
Orchestra To-do - When you’ve misspelled your email address during sign-up, it suggests your correct email address.
Gmail - Suggests other people you might want to mail to as well, based on previous group emails you’ve sent.
/via Tal Benisty