The alpha client is going to be updated to allow hosting a vault "shortly" according to their release announcement but as of this moment it is still client only.
Don't hold your breath or anything but I do believe the team when they say it is coming very soon, likely within a few days.
well, if it gets online before storj does (who still isn't open to public testing yet) I have no problems bringing a decent amount of hosting space to the network!
I stand corrected re: storj
it's currently in public beta, but the rewards are minimal. Very minimal.