The GNU GPL requires access to the program and the sources. Through a webapp, you never actually use the program, but feed data into the webserver which will run the program and then send you back the results.
So... the user is "using" a GPL program, but has no way to get it's sources.
Hugs, Rui
In the case of a server-side solution (like PHP scripts) the end user does not actually run the program. All he gets is a quite static HTML document (well not so static if it as Javascript, applets or other client side runnable content). In fact your are not provided with a program but with a service. So your not the user of the program.
IMHO the actual user of the program is the owner/webmaster of the server who did intall and configure the program. For example my ISP is free.fr and I'm writing this using the IMP webmail interface (which is free software as far as I know) it provides me. Can I say that I'm an user of IMP? I don't think so. I'm an user of the free.fr web services, whatever it uses to provide it (even if I like to know that they use free software).
Well, now if the pages does contain some Java applet content wich are actually runned client side on my computer, I'm puzzled. Am I directly using foo.class so I can say I'm a user of this program or am I just an user of a browser (Mozilla in this case) which provides me the features of foo.class? Can a GPL'd browser run non free applets?
The problem is that the difference between what is a program and what is a (dynamic) document is not really clear for me.
Guillaume Ponce http://www.guillaumeponce.org/