licensing

I have a customer who wants to build a SaaS platform that they would like their customers to subscribe to and create and collaborate content, publish, launch email campaigns and track the campaigns. am wondering if we can take Drupal and build modules on top of it and host it as a SaaS service?

I understand the code that we build has to be under the Drupal GPL norms. But does the GPL support this kind of a business model?

Is it possible to sell an online service (SaaS) that is based on Drupal without being forced to distribute my PHP module source code?

KeyCAPTCHA external service is based on KeyCAPTCHA plugin(s), installed on protected web site servers.
This plug-in provides running the obfuscated client-side JavaScript (or ActionScript, if browser is not HTML5-compatible) coming from keycaptcha.com back servers.

Since these KeyCAPTCHA plugins are also published as Drupal.org modules (or extensions?) in http://drupal.org/project/keycaptcha, they are under GPL.

Drupal Design sub site will allow uploading of design files for sharing with other users. There are three main sections to the site:

• Challenges - where users contribute and collaborate on design problems for drupal.org, drupal projects, drupal core and so on.
• Assets - where users can upload and download high quality layered design files such as icons, templates, textures and so on.
• Discussion - where users can post comps for discussion, collaboration, feedback and so on.

Is this kosher if the other product is also released under the GPL? It seems like it would be, but I'm wondering what people's thoughts are? Here's the concrete example:

I was searching around for licensing policy on Drupal, specifically, releasing patches and modules from copyright (into public domain). I came across http://drupal.org/licensing/faq#q7 where item seven states "Drupal modules and themes are a derivative work of Drupal" and additionally implies that this is true for all works, hosted by Drupal.org or not.

This is in context with third-party commercial Drupal templates/modules/extensions available from popular vendors e.g. TemplateMonster.

Drupal is licensed under GPL 2. And according to GPL 2 terms, no software based-off a GPL 2 software can be sold, or any restrictions placed on its redistribution.

Any according to GPL 2 terms, Drupal modules and themes are based-off Drupal (because they interact with Drupal).

Most of such vendors sell Drupal modules/themes with single-site/domain license. So, I have 2 questions here:

If someone uses Drupal to build a custom "software as a service" web app (an example mght be basecamp [http://basecamphq.com/]), is there any way to prevent a competitor from getting acces to the custom code or configuration used to create it and starting a competing service?

I'd like to release a couple of themes through d.org. All my themes are built using Eric Meyer's browser reset stylesheet which is in the public domain. I'm also thinking about incorporating public domain images in my themes, such as photographs from the NASA archives. At the same time I'm aware of the restriction that only GPL'd files are allowed into the repository. What am I to do?

I want to use Drupal as a paid service for building Web sites and communities. The Drupal instances and modules would reside on my server. So basically I would be acting as an Application Service Provider. If I pursue this endeavor I will likely end up using the Drupal core, some contributed modules, and several custom modules.

Does the GLP License require me to make available any of my custom modules, configurations or patches made to Drupal?