You say "In fact, it goes against the very ethos of Hacker News.", do you think your action aligns with the "ethos of Hacker News"? Do you think it's okay to rip-off something just because you think it shouldn't be invite only?
Yes?
When the idea is the design (as is the case with visitor.js), no there is not. In both cases, it's taking and reimplementing wholesale (but from scratch) the closed product into an open-source one.
But if I you take the design and make your version look the same, then it's a rip-off. Yes, you modified it. But please put both versions next to each other and tell me they don't look like each other. As long as you don't have an original design it's a rip-off for me.
http://bobcargill.files.wordpress.com/2010/08/geocities-izer...