Comment Re:Vs. Mootools? (Score 3, Informative) 154
I can't see anything on their webpage that indicates that they have a strange interpretation of the GPL v3.
I get the impression that they believe merely using ext JS on a public website is distribution. I would agree with that. Therefore, if you modify the code, and then distribute it, you have to release under GPL v3 to be "legal". I don't see anything wrong with that.
You don't have to modify the code, and therefore, you don't have any obligations.
In either case, you don't have to worry about the source code requirement, because the source code is being downloaded by the browser anyway.
Regarding server side code, that's different. You aren't distributing the code, you are merely presenting the results of the code. I understand that in the USA and Australia at least, that it is not possible to copy right the output of a program (at least not in general cases).
So, you can take WordPress (which is released under the GPL), and modify it all you want, and so long as your modifications stay on your server, you have no worries.
This "hole" in the GPL coverage is "closed" by the AGPL, which mandates that if you modify the code, and use it, then you have to offer a link to download the changed source code to anyone who accesses the program over a network. (Or something like that anyway, see section 13.)
The question of which is more appropriate, depends on who you consider the "user" to be, the public, or the web master.