A new application, Postcard, launching today, will help you cross-post to
various social media websites, but with a few unique twists. Unlike similar
tools, this "Swiss Army Knife" of an app lets you set any one social network,
or even your own website, as the content's host. So, for example, if you run
multiple Twitter accounts, the app could allow you to tweet from one, while
the others re-tweet you. In other words, Postcard is a pro tool designed for
those whose job likely involves social media management of some sort.