I've been contacted by the Department of Defense to help with the effort to get out the expat vote. Now, fear not--the DoD is not going to come after you with a drone. The particular branch handling this aspect of extramuros living is FVAP (Federal Voting Assistance Program) and they're responsible for, amongst other things, the new widget on the right, which will take you to the FVAP page that will let you get your absentee ballot. You'll be taken to a page where you can register for your absentee ballot, or request it.
One thing you will need is a printer--if you're registering for your absentee ballot, you'll be required to send in a physical sheet of paper with physical envelope. Oddities, I know, in a rapidly-electronic world. But otherwise you can receive your ballots via email, or snail mail, if that floats your boat.
Voting isn't exactly Gangnam--you don't get high-fives if you video yourself walking into a curtained booth (yeah, I voted old skool) and punching a button. The statistics for voting are quite dismal: you're not going to be the one vote that changes everything. And afterwards, you're still the one paying $4/gal for gas (well, if you drive, that is, which I never did) and trying to cobble together dinner for 4 for $2. So why bother?
I used to wonder the same thing, myself. And then I came upon a wonderful rant (which, unfortunately, I can't link to, because it discusses partisan policies) which still gives me my reason to bother sending in my paperwork and casting a ballot: A government "by the people, for the people" means that we are the government--that's sort of the definition of a democracy--and we don't like something, then we can change it, through a vote. If you call up your cable company because you're not happy with the service, you might get a refund, or you might get an apology, or you might get a repair guy tying up your lines for two days. But when it comes to changing the company, you're pretty much stuck in the mud. On the other hand, if your elected leaders do something you hate, you can vote a new crop into office, and in the House, this happens every two years. This is about as close to being the master of the world as an ordinary citizen will ever get. Sure, you could also win the lottery. But voting gives you better odds.