Guys, this is what lawyers do all day long, they send legal notices to small companies hoping to get them to pay some licensing fees for the patents/trademarks. Nothing new here, of course any court Judge would laugh this aside, I doubt they'd even invest the cash to take Mojang to court but once in a while they'll scare that small indy dev into forking over some cash which makes it worthwhile. Lawyers do that any time they're not actually properly suing people who are really infringing on them so they earn their keep (In fact if I employed a Lawyer who sat around waiting for someone to infringe on me before doing something I'd fire them for being lazy).