Cubesats are neat, basically a small, modular-ish common form factor and bus brings the bar down for building your own space probe (PC architecture anyone?) Generally though, they don't have propulsion right now, they just orbit until they re-enter and are destroyed. Many folks are working to change that, most interestingly Deep Space Industries which swear they'll be launching a commercial asteroid mining mission this decade using their Comet-1 engine which is literally a steam engine with a charming Isp of 175s. The idea of using water as your root propellant isn't crazy of course: it's inert, safe to handle and launch, safe to have hanging around on the ISS (unlike hydrazine which hates you) and extremely common in the solar system. It's such a good idea that there are a few other folks working on similar systems: HYDROS, which electrolyzes the water into H2 and O2 and burns that for a respectable 300s Isp, and CAT (which might be the same as the one from this kickstarter!), which just turns it into a plamsa and claims a totally absurd 1623s Isp. That's ion engine territory.