The Three Modes of Travel
Ships in Elite: Dangerous can use three distinct modes of travel, for travelling exponentially different distances:
Hyperspace jumps - hopping around within or between systems in near-instantaneous jumps, but with limited control of exactly where you end up
Super-cruise travel - roaming about at high speed within a system
Conventional flight - moving, fighting, docking and mining in a smallish area of space
Although each mode of travel has different properties and uses different in-game technologies, for readability this post will talk as if ships had a single engine with three gears - a "top gear" that's the next best thing to teleportation, a "middle gear" that's optimised for urban transport, and a "first gear" that goes at walking speed.
Meeting other players
Real-life technical considerations mean players can only interact with a small set of other people at a time, usually called an "instance" (although this particular proposal uses the word "session"). Switching gears also punts you into a different instance, and there are three ways to try and follow someone into a new instance:
Flight control - friends can let each other "slave" their drives together so they all change gear at the same time (and in middle gear they can all travel in formation)
Follow the trail - switching up into middle gear leaves a Back to the Future-style flame trail you can follow, and switching into top gear leaves a residual opening that can be analysed (or in extreme cases tailgated)
Pray to the matchmaking algorithm - the game will generally try to put you in an instance with other players you would enjoy playing against, so you might bump into your target without doing anything special
None of the above are guaranteed - for example, you can't slave a huge pirate gang together and force your way into a nearly-empty instance. But with a bit of skill you can play a good game of cat-and-mouse with all this gear-shifting.
Interstellar snooker
Although you can plot any route at any time, players will usually aim at a point in space, shift up to middle gear to get in position, up to top for a the long haul, down to middle gear to get to their approximate destination, then finally down to first gear to interact with the world.
But no matter how fast your top gear is, a straight line journey to the dark side of the moon is still going to leave a pancake-shaped splodge on the moon's near side. If your ship was a snooker ball, you would need to bounce it off the cushion to make a shot like that. So what does a cushion look like in space?
Well, super-cruise travel works by warping space, which means it warps gravity too. That will make a ship that normally handles like a bumble bee fly like more like a whale in tornado, but it also means a careful commander can do a real-time gravitational slingshot - making a hyperspace jump to Mars, a quick half an orbit around to line themselves up for the moon shot, then a hyperspace jump back to the part of the moon they were aiming for.