What do you do when all your data is in "the cloud", and the cloud "bursts"?

That is the question being asked by users of social bookmarking site ma.gnolia.com this morning. Ma.gnolia are just the latest in a long line of services that have disappeared or lost user data. In this case getting the data back appears to be reasonably straightforward (use the rss Luke!), a bigger question will be how to use this data.

I have a few rules of thumb on what I look for in a service, but first, and most important, do I place any value on this data? Do I care if it vanishes overnight? If not then I ignore most of the following.

• How do I get my data out of the service? Useful for backup and migration purposes
• If I can get the data out, what about meta-data like state, i.e. details of unread/kept messages in services like Bloglines or Google Reader, a roster from an IM service, message states and address books from webmail.
• Can I easily put data (and state) in a standard format back into this service?
• Can I run this service or similar with minimal hassle on a box at home? I could be mad, but I'm not overly keen on giving up control or my data to others.

What's the big winner? Open standards, imagine that Gmail ceased to be available as a free service, you could use imap or pop3 and take your email elsewhere, similarly opml for an aggregator. Sure these examples don't include meta-data, but you've covered the basics.

When you hand your data to a silo, can you get it back in a usable form?

Update: Kevin Smith from the Psi Jabber/XMPP Client project has written a useful tool to migrate your data between xmpp servers, try doing that between MSN and AIM...