Moving from Posterous to WordPress
There is an backup function now within Posterous (which was a feature promised by Twitter), but so far I’ve not heard of anyone who has managed to get it to produce anything. It gets stuck on “finalizing”.
WordPress (self-hosted) doesn’t have a Posterous import plugin anymore, so many people have been using wordpress.com as a middleman. The import from Posterous function still exists there and works. From there you can export and import to a self-hosted installation.
One problem for me was that UX Podcast was a posterous site with audio attachments. The migration via wordpress.com didn’t really help enough. So what did was to mirror the site as HTML files using Teleport Ultra. I then did some batch editing of the posts using Notepad++. Finally I used a plugin called HTML Import 2 to import the body from the posts to the new WordPress site.
I haven’t found an easy way to move the comments. I had located a script that made use of Posterous’s API, but the API has changed so it didn’t work. Importing to wordpress.com does grab the comments. Thankfully the site has very few comments, so I’ll probably do some XML editing using exported data from there.