At the bottom of many blog posts (including this one) and website entries you're likely to find a widget that allows sharing to social sites or emailing to a friend. ShareThis competes with other systems like AddThis and SocialTwist to give publishers an easy-to-install sharing method.
Kippt, designed to make information workflow and archiving effortless, has launched a new API alongside a developer site and app gallery. The new, publicly available API simply opens up the existing Kippt API that continues to power the Kippt web service. Instead of pushing Kippt as a standalone product, the Kippt team hopes that the Kippt API will encourage developers to develop apps based on the Kippt platform.