Yes! "The open source counterpart of Google Apps" indeed. The thing that motivated me to do this in the first place was observing that we have whole open source desktop environments containing just about everything many of us need on a day-to-day basis, but in "The Cloud" open source options seem totally lacking. I use gmail. What else can I use? There are many open source web mail clients but to use them I need to run my own server, which is too much friction for me.

But if I could just install an e-mail client on Sandstorm with a couple clicks... I'd totally do that.