Why I care who's paying

A while ago I posted this while mulling over a task manager web app called NirvanaHQ. Although I flirted with it for a while, I've decided it isn't for me in its current state. I've just registered for Wunderlist which looks promising, but the same questions rear their head: If it's free, who's paying?
The reality is that somebody must. There's a reasonable sized team behind Wunderlist. The software is pretty and seems to work. That takes a lot of time and effort. Then there's the hosting. It's quick and responsive and seems to have a reasonably large user base... all of this costs, yet the service is free and there's no advertising.

So who's paying? I've got two reasons for wanting to know.

You may have come across the theory that Google products are not search, adwords or google apps. No, they're the bait to bring in the people. We're the product and Google sell us, the users, to advertisers.

I think that comes from a reasonably bleak view of the world, but there's definitely something to be said for the amount of information that's put in hands of technology companies. So if my information has a value to anyone other than me (which I seriously doubt), then I'd quite like to know what's happening with it.

Ignoring the paranoid view of how my every thought and movement is being logged and offered for sale later, what really matters to me when looking at a service like Wunderlist is: does the company have a sound financial footing, a good business model, the ability to retain staff. In short, if I start using this service will it still be there next week?

NirvanaHQ has been in beta for a long time now. My understanding is the company behind it does other web development. Perhaps this has been paying the bills. Wunderkit, who develop wunderlist don't seem to charge for anything they do... While cost free is a lovely thing when the news keeps saying we're in a time of austerity, how can I know it's reliable in the medium to long term once the investment capital has run out?

I know the sensible thing to do is acknowledge the business acumen of the venture capitalist who has given this startup a whacking great chunk of cash. Unfortunately there have been too many cases of someone taking that cash and blowing it all.

In which case, what happens to all my carefully planned tasks?