I am 1181 out of 1500 on plundering.
I plunder because people have stuff and I like stuff.
I go for FP's first. I'll check in several times before the 24 hours is up if I see FP buildings. Then I go for HoF's if there, followed by Goods, supplies, and coins. Coins I take if the Plunder timer is near expiration. Don't need coins, but gotta plunder something for chance at BP's.
I don't pay attention to who Aids or not, I just start at the top of my Hood and work my way down. The only way to be safe is to fight back or send a friend request. Even if they can't break my defense, as long as they keep trying I'll give em a break.
The best reason to plunder? Hate mail. I LOVE hate mail. Makes me all warm on the inside when I can push someone to writing hate mail over nothing. Just a game ya'know.