Twitter - Characters exceeding the 140 limit are highlighted in red.
/via Simon van Woerden

Twitter - Characters exceeding the 140 limit are highlighted in red.

/via Simon van Woerden

Tweetbot - When replying to a tweet, swipe down to see the original tweet and author.
/via Kevin S.

Tweetbot - When replying to a tweet, swipe down to see the original tweet and author.

/via Kevin S.

Twitter - If you enter your own username, the validator alerts you.
/via @_augustobianchi

Twitter - If you enter your own username, the validator alerts you.

/via @_augustobianchi

Twitter - If you follow a “Tweet” link when not signed in, the Twitter dialog window allows you to sign in & Tweet in one action.
/via Rich Dooley

Twitter - If you follow a “Tweet” link when not signed in, the Twitter dialog window allows you to sign in & Tweet in one action.

/via Rich Dooley

Twitter - iOS app gives feedback in the status bar when you Tweet.
/via Sebastian Hall

Twitter - iOS app gives feedback in the status bar when you Tweet.

/via Sebastian Hall

Twitter - When submitting the same tweet twice, an error message is shown.
/via Sindre Sorhus

Twitter - When submitting the same tweet twice, an error message is shown.

/via Sindre Sorhus

Foursquare - Allows you to import your bio from Twitter
/via Mel Hambarsoomian

Foursquare - Allows you to import your bio from Twitter

/via Mel Hambarsoomian

Twitter - The registration page uses a casual tone of voice in its validation confirmation messages.
/via abhimanyu

Twitter - The registration page uses a casual tone of voice in its validation confirmation messages.

/via abhimanyu

Twitter - On the mobile version, the error message lets you know that typing on a phone stinks.
/via @oi_joris

Twitter - On the mobile version, the error message lets you know that typing on a phone stinks.

/via @oi_joris

Twitter - After you change your password, the system reminds you how many apps have access to your account and lets you review them.
/via Rolando Murillo

Twitter - After you change your password, the system reminds you how many apps have access to your account and lets you review them.

/via Rolando Murillo