General word of advice: don't reflexively type /home before you've actually reset your home, or you'll find yourself standing at spawn, possibly with an uncomfortably-close zombie. That goes double if you don't even remember your home coordinates. That whole Nether system was a godsend, though it took a few false starts to find my way back to my connecting path. (Sidenote: holy crap that is complex now. You guys have been crazy busy. Also I should have Sandwich show me how things work around his place, since I don't recognize half of those farm mechanisms anymore.)
Okay, think I have at least the basics of GriefPrevention figured out. Plop down a chest to stake your initial claim, click on the borders with a golden shovel to expand it, use a stick to turn the borders off and on. Then just do something underground to extend the claim downwards. Simple enough. Here's my question though: will we have any mechanism set up to earn expanded claims sizes? I hit the limit much sooner than I expected (squared numbers are fun like that), and while I did cover everything I've actually built, in an ideal world I'd like to plop a rectangle around my entire island. I understand if that's not possible though.
One little downside to this system versus some other protection systems I've seen is that there doesn't seem to be any way to designate an individual chest as "public," so that you could for instance have a spot for visitors who aren't on your trusted list to grab stuff. I guess you'd have to get creative with your claim borders, creating a few adjacent ones and leaving a small unclaimed public rectangle for chests like that. At the very least I'll make sure to add the usual suspects to my trusted list as I see you in game.