@Gargron I've found we have to simply it even further. Mainstream people might know "decentralization" as a term, but not what it really means. The most simple explanation I've come up with for friends and family who can't detach themselves from Facebook...
"It's like Twitter or Facebook, but they all can talk to each other, and the one you join is like your "home base." Then imagine no matter which one you're on, you can talk to people on all the others!"
They still don't get it tho. :D