Even big "safe" companies like Microsoft and Google discontinue services. It's probably better to accept the fact that services come and go as the price of progress and figure out how to live in such a world.
This is actually one of the ironic casualties of the cloud. In the old days you bought your packaged software and it was pretty much guaranteed to work as long as you didn't change your setup (OS, hardware, etc). With cloud services the change is out of your control, so there's nothing you can do to freeze your setup.
This is probably a reason why there may be a growing market for personal clouds.
"This is actually one of the ironic casualties of the cloud. In the old days you bought your packaged software and it was pretty much guaranteed to work as long as you didn't change your setup (OS, hardware, etc)."
And this led to a lot of other problems, for example, you couldn't keep up with new technological innovations because you needed older systems for some programs.
It's an interesting question, which practice is better.
I think the best approach is to make sure whatever service you decide to use has good import/export features.
A boss at a job I worked at a few years ago still keeps his contacts in an ancient version of Lotus organizer without VCard export support. As a result he's pretty much locked into it unless he ponies up $100 for the latest version of the software (released in 2003) which has VCard export. He's too cheap to do that so he'll have to stick with it as long as he is still on a version of Windows that supports 16bit software.
I gave it a try in a VM for a few hours, hoping to find a replacement to Dropbox and Box.net.
Without diving into the source, my primary complaint was that the whole thing felt unpolished. There were display errors that just needed some TLC, documentation that sorely needed the eyes of a proficient English proofreader, and issues that made me wonder if there were going to be underlying security concerns. (For example, sometimes the path in the URL would be encoded, sometimes not... just makes you wonder what's lurking under there.)
This is actually one of the ironic casualties of the cloud. In the old days you bought your packaged software and it was pretty much guaranteed to work as long as you didn't change your setup (OS, hardware, etc). With cloud services the change is out of your control, so there's nothing you can do to freeze your setup.
This is probably a reason why there may be a growing market for personal clouds.