This is why people like Stallman warn about the cloud, at the extreme end of things. But usually these services offer a way to back up your data, at the very latest close to whenever it is time to finally close up shop. :-) I personally use Pastebin.com a lot and have a lifetime account there, but any information that's really important I immediately back up. For me it's important that if I can't make backups or export the data, at least it's in e.g. plain text so I can get my data out without losing anything.
I have gone back to using LibreOffice quite a bit, too, in lieu of cloud word processors. I use the cloud stuff when I'm not working on mission-critical data.
Essentially, the more nuanced you can be about what you'll post where, the better your results will be. If you have to pick the One True Software, you're screwed one way or the other.