Some of our users had the same concerns when we made our site featurelist.org. That's why we added (due to a user's feature request) a way to export all data from your project to XML.
Without exports like that, users will become even more wary of storing their data on sites that aren't supported by the "big 5" internet/software companies. There's always the risk the company (or handful of hackers) will go away and take their hard work with them. It's also a differentiator when you do that because the big guys want to hold onto the data.
Obviously an XML dump is not the same as having the full service, but at least, if bad things happen, the users can salvage some of their content without digging through Google/wayback caches.
The problem with xml dumps is that it is a backup-like feature, and users are notoriously sloppy with backups.
It is great that you provide the feature (and I'm slightly embarrassed that http://scribbl.net/ doesn't) but what users really need is the ability to get their data after the application has gone down. Not that I see any way to do that given the current state of the internet.
This kind of thing is why "the cloud" is going to have a hard time serving bigger companies. Security, regulatory compliance, reliability, accessibility of data, etc. are all things that are historically not being well-served by even larger companies, and I think they're the reason a lot of "Web 2.0" companies are unable to make their way from success with consumers into enterprise markets (where a single sale can make your month a good one).
Wufoo have managed to do it extremely well. They provide great export features, and they go to great lengths to explain how and why they provide reliable and redundant infrastructure.
But the good examples will be dragged down by the bad examples, and the end result will be much slower adoption of the model. So, going off-line without warning and without providing a means for customers to get their data, is a great disservice to not just your own customers but to every other hosted application provider.
I don't want to pick on the Stikipad guys in particular, but it's a real problem--if you aren't sure that you'll always be around to serve your customers, you need to make a dead man's switch plan to get the data back into the hands of your customers.
I rely on Toggl for time tracking (which I then use to bill my clients), and Google Docs to maintain my various (and extensive) list of accounts, as well as various documents essential to my business.
If I lost either I'd be screwed. I'm not so worried about the Goog, but Toggl (and before that 14Dayz) does worry me a bit.
Stuff To Do has time tracking features. It's not quite as advanced as Toggl in some ways, but it's now open source, as I decided that that market is way overcrowded. I still use it myself though, and would be happy to have a few collaborators.
Without exports like that, users will become even more wary of storing their data on sites that aren't supported by the "big 5" internet/software companies. There's always the risk the company (or handful of hackers) will go away and take their hard work with them. It's also a differentiator when you do that because the big guys want to hold onto the data.
Obviously an XML dump is not the same as having the full service, but at least, if bad things happen, the users can salvage some of their content without digging through Google/wayback caches.