legal gpl

http://drupal.org/project/zend_feed

That requires a third party non free library. I am not trying to troll btw, please don't see this as that. For me to understand what is going on, i need concrete examples.

The way I understand this is:

1. if drupal talks to code at the php level that code must be GPL, it DOES NOT MATTER how the code gets to the server, if they are going to call each other all code must be GPL

2. this does not apply if the code runs on the client side, javascript,css,etc

3. web services are exempt