There is a good post on backing up a PLE or really anything created in the cloud. The danger of working in the cloud is the site disappearing like Ma.gnolia recently. When the data is important, such as for teaching a class, this is huge.
So the advice to have additional copies elsewhere is good. Is it the only way? I like the concept of cross-posting better than backup and restore to alternative sites. Instead of regular exports and imports, as the data is generated in multiple places at the same time. Think of it as an near instantaneous export and import to minimize the loss.
- Blogs: Ping.fm sends blog posts to Blogger and WordPress and LiveJournal. Zoundry Raven, a desktop blog editor, can also cross-post.
- Bookmarks: Diigo can copy saved bookmarks additional services like Delicious and Simpy (and still lists Ma.gnolia).
- Status updates or microblogging: Ping.fm also can handle cross-posts toTwitter, Facebook, Friendfeed, Identi.ca (and many more).
Perhaps more opportunities for cross-posting would make the Interweb a safer place for our data.