If you've been using Blog Riffer (formerly known as SEO Content Factory) to post to Posterous, you should know that Posterous announced today that they'll be shutting down as of April 30.

You'll want to migrate to another platform before then. According to their blog, WordPress and Squarespace offer importers to ease the migration. If you want to continue posting to your blog using Blog Riffer, you'll want to go with WordPress, since Squarespace isn't currently supporting any sort of 3rd party API access.

Another option is outlined in this article from LifeHacker, which describes how to get your data into a Blogger or Tumblr blog, both of which Blog Riffer supports.