Are your digital memories going to be there when you're old?

I have recently been reading (auto)biographies of famous musicians. (Dietrich Fischer-Dieskau and Gerald Moore) One of the things that makes these books so enjoyable to read is the quotes from letters that they wrote or received. This lead me to consider how the historians of tomorrow will chronicle our lives and interactions. Not only that, how will we remember our own past?

I am sure that we all have a box somewhere of love letters and mementos of the intimate moments in our lives, but increasingly our correspondences are not written down on paper. Perhaps your email client (Outlook, Mail, Thunderbird) saves all your emails and that seems like a good enough way to keep your memories. But what about when you switch to a new mail program/computer/operating system? Will you make an archive copy of these emails so that you can read them when you are old? Do you know how? Its not that easy. And it gets worse.

What if you have a web email account like yahoo or gmail. You probably don't even have a copy to call your own. Believe it or not companies do go out of business. In most cases, services like this have features to download archival copies of your email, but they are not always easy to figure out, and they don't always leave you with very readable results. But wait, it gets still worse.

What about your Myspace or Facebook account. This article brings up the very good point that for these type of services, its nearly impossible to get a backup copy of your interactions with others. And as social networks are only as useful as they are popular, what happens when all your friends realize that Myspace is far inferior to Facebook and switch over? Will you abandon all those messages? What about when everyone leaves Facebook for the next big thing?

What do you do to keep your memories safe?

P.S. Do you archive those jewel-like text messages that made you grin like an fool or broke your heart?