A service that involves the repeated sending/receiving of data, (in this case email) incurs a cost over time that someone has to pay for.
There are three solutions to this issue:
A. Run a free service until you run out of money. (not sustainable)
B. Run a free service subsidized by ads. (user-hostile and possibly unsustainable)
C. Charge the user a subscription fee. (fair and sustainable)
Unfortunately, the perception that email and other services should be free has permeated society. The internet made the transfer of information cheaper by many orders of magnitude, but it is still not free.
> Where the money will go... Hosting. We need some serious hosting space to deploy our storage-intensive services.
Money going towards mobile dev makes more sense although is much more risky to back given the short timeframe and limited budget even if they meet their goal.
0: "Your email is never stored on our servers, and is left on your current email servers."
I think my point still stands as a general principle though, its applicability (or the lack thereof) to this particular service notwithstanding.
It's time we move forward, I think. I used not to like the idea of subscription, but I'm finding it cheaper now.
Edit: From their FAQ:
Mail Pilot is more than an app; it's a comprehensive online software
service. It runs on servers, and delivers and syncs content between
every Mail Pilot app that you might use.
You can access Mail Pilot through a number of desktop, native
mobile, and web applications. To make this possible, Mail Pilot adds
services to your existing mail accounts that it syncs between all of
your devices. Our servers store metadata about your messages (not
the messages themselves, however!) to bring to you the reimagination
of email that so many have come to love.
Mail clients can get away with charging one time. Our apps are all
free, but the service is paid for, much like other online
productivity and email enhancement services.