Over at Redmonk, Stephen O’Grady has written a lucid analysis of the debate over whether or not the premium WordPress theme Thesis (really all WP themes, including themes for which developers charge money) have to be licensed under the GPL. Is it even possible to say that a WordPress Theme is 100% derivative or not? There are people who are trying to make that claim but if it was true then all the functionality that is included in Thesis for instance would be already included in WordPress, right?
This may seem like an issue out on the margins but if you think we’re headed towards a future where people build on the creations of others–which by the way would apply to the past as well, ahem– then you might find this interesting.

