Because I've received numerous e-mails about Master Level Chess, and because there is already a discussion about it on another popular computer chess message board, I'll state my opinion here. The below text is copied from a post I wrote on the Computer Schach und Spiele message board earlier this afternoon, with some minor edits:
I haven't downloaded Master Level Chess, but based on the information I have seen, there is little doubt that the program is technically legal. Glaurung is free software. This means, among other things, that you are free to use it as a basis for your own software, as long as all users/customers are given access to the source code (including all your modifications), and the freedom to use it themselves under the conditions of the GPL. In this case, it seems that the source code hasn't been changed at all. The "About" dialog still contains links to the GPL license text and to the Glaurung source code, so everything seems to be all right.
Whether it is ethical is another question. I don't mind the existence of Master Level Chess myself, and I don't feel that the authors (or "authors") are stealing anything from me. After all, Glaurung is free anyway, so I don't lose any money. On the other hand, I do understand if some customers feel a little pissed if they pay for something and then discover that it doesn't add anything of value compared to a free product. Because I am hardly a neutral party, I am not the right person to judge whether the improved graphics in Master Level Chess is worth the small amount of money they charge. If you like Master Level Chess better than Glaurung, and think it is worth the money, that's great. If, on the other hand, you think it is a blatant ripoff, just express your opinion by a negative review, or complain to Apple.
I also don't know whether Master Level Chess breaks any of the rules for the iPhone App Store. Again, this is not for me to decide. My personal opinion about Master Level Chess simply doesn't matter; the concerned parties are Inner Four, Inc (who earns money from the product), the customers (who pay for the product), and Apple (who makes it available, and also earns some money). If Inner Four, Inc is stealing something, it's from you, not from me.
There is one thing that does annoy me, though: It seems that Inner Four, Inc hasn't bothered to change the support e-mail address, so all e-mails go to me.
Finally, even if some of you do prefer Master Level Chess, I advise you not to delete Glaurung quite yet. There'll probably be a new version soon.
