Here's yet another example of the tradeoffs of the "cloud." I use Gmail and Google Docs and other kinds of Web applications. My data is stored on their servers and I have no guaranteed access to it. It's convenient - but I know it's also dangerous.
For instance, I saw on Slashdot just the other day a post about MySpace buying imeem, a social networking site very focused on music. If you go to imeem now, you are sent to a MySpace redirect page. It says:
Where's my imeem profile/playlist? MySpace is working to migrate your imeem playlist to MySpace Music. We'll email you about that once we have more details.
... because if you really loved and used your imeem playlist it's gone for now - and there is no guarantee that you will ever get it back. If imeem was the way you kept track of music you felt strongly about, it might be lost to you forever. There's no obvious way of breaching the mile-high wall of MySpace to demand your imeem information back. You just have to wait patiently for Rupert Murdoch's underlings to open a door for you, or not.
Periodically I do copy all my stuff on Google Docs onto my own computer because I am paranoid about relying on Google to be nice about allowing me to use its server space. I see on monkey_bites that Google Docs is adding a feature that will allow you to export all your documents as a .zip file.
I don't download as often as I should, and maybe this will help. Still, I can feel, deep down in my inner procrastinator, that the day is going to come when I stop bothering. Heaven help me if I type docs.google.com into a browser one day and get a redirect page like that one the imeem people are seeing right now.