User blog comment:One Of Terraria's Best/My Main Question/@comment-25406792-20140911013139/@comment-3157150-20140911030853

Open source would be a horrible idea (in terms of sales) for Terraria. It's just not viable as a method of earning a similar (even slightly so) amount.

Also, something that you may have missed on the Terraria Online website regarding Mac/Linux ports.