Destiny as a series has had a Refer-a-Friend program floating around for a while, but they've just announced a new update that's on the way on October 30 through their weekly update blog post.
It's specifically for the recent Forsaken expansion and after using referral links you'll earn a ship, emblem, and sparrow -- all chameleon-flavored. To be a "veteran" and connect with referrals you simply need to own Forsaken: if you're a "new player" you need to have never owned Forsaken or have only owned it for "less than seven days." There is a grace period though through November 7 -- anyone who bought it between October 16-30 will still be able to qualify as a "new player."
It's a decent time to get into Destiny 2 if you've been holding off, but it remains to be seen if the sprinkle of micro-DLCs over the course of the next year will be able to keep it interesting long term.
This Week at Bungie [Bungie.net]