re: Poker & Min 3 bets?
I would recommend almost never using this strategy. It doesn't allow your opponents to fold, it gives your opponent info on your hand if they notice it, it doesn't build the pot much and it's generally just quite pointless. Maybe you could use it to induce a really aggressive opponent to come over the top, but I would usually either be wanting to see a flop with an opponent like that, or maybe just raising really big so that they'll call a huge raise with utter trash. Don't do it...
As for what hands an opponent is likely to have when they do it, I often think that micro stakes players use it for all their 3-Bets when they are very strong, and will often be the type of people who very rarely 3-Bet in the first place. Obviously you never fold to a min 3-Bet, but just bare in mind that your opponent is probably quite strong and so you shouldn't get to attached to a flopped pair.
Hope that helps!