This better not be a waste of my time! (Not that I have anything better to do)
it's a massively multiplayer game where you travel between star systems in a galaxy. (This galaxy contains only around 200 stars). It is very involved: you can make money through colonies, trading, doing barge runs for rich guys, hunting bot ships, ferrying passengers, selling artifacts... The only limiting factor is that everyone gets a max of 5000 of fuel and it only builds back up over time.
You also have to pay rent to stay somewhere in safety while you're not logged in (unless it's a colony you own, in which case it depends on its defenses). Some star systems (and colonies) are under UN protection, which mean you pay taxes for each hour you stay there. You can also take you chances in some empty area in the galaxy and hope that nobody comes across and destroys your ship