Requires iOS 6.
Send selected text, images and URLs quickly to Facebook, Twitter, Sina Weibo (新浪微博), Mail, Messages, Notes and Reminders.
Wherever you can select something, you can send them.
It may take some time before the composer shows up if the selected content is large or contains images.
For iOS 7, check QuickShare for Action Menu (iOS 7).
See larger Screenshots below..