Interesting idea. I've started using a few more cloud apps lately, and the thought of losing everything certainly crossed my mind again. The problem thought is often the data is tied to some sort of object structure, which may be hard to replicate. For example, lately I've built a couple of mind maps on MindMeister that I would not want to use. However, the data mostly has meaning in the mind map structure, and having it in raw form, while better than nothing, would still mean I would need to convert it into something workable again.