Recently, blogging service Posterous thought it would try and help ease the burden of moving from other places on the web to its blogging Platform by developing a bunch of migration tools. All of these tools were built on other services' open APIs and designed to go in, grab your content, and republish it through Posterous maintaining as much metadata as possible. Things were fine until photo-hosting service Twitpic caught wind and cut of Posterous' API access.
Twitpic's stance is somewhat understandable, but not really fair. Twitpic developed and offered its API so that developers could integrate with its apps and use its service in new, creative, ways. It certainly didn't intend for a mashup app designed to encourage users to leave Twitpic.
So here we are, some time later, and still wanting to move our pics from Twitpic to Posterous. After trying to get Twitpic to play ball, Posterous has finally released an Adobe Air-based migration tool to handle the process. The tool uses your Twitter credentials to go in to Twitpic (which uses Twitter for Authentication) and grabs your photos, and manually moves them to Posterous, using your desktop as an intermediate archive.
Currently, Posterous' tool is available to facilitate Twitpic to Posterous migration, but plans to make the project open source so other services can design tools to help users get their stuff out of Twitpic.