I want to provide a hosted solution using open source software. I intend to charge a fee for users to create a website (hosted by me), part of which will be powered by modified open source software. The user will not have access to the source code (the files on the server) and can only control their site through a web interface. Is this allowed under the terms of the license (GPLv2*)? I assume that since I'm charging for access to my service rather than actually redistributing anything, it shouldn't be a problem but just wanted to make doubly sure. Thanks in advance for any advice. * http://opensource.org/licenses/gpl-2.0.php