All forms of collaboration require some sort of centralized collaboration tool.
In Drupal this can be implemented with "Multi-Sites", "Organic Groups (OG)", and "Domain Access". These solutions all have their strengths and weaknesses.
The main issue however is when to choose "Multi-Sites", "Organic Groups (OG)", or "Domain Access".
First a short overview of the relevant points:
"Multi-Sites"
When you need to add your own php functions to drupal, you can simply embed them in the content, but that is not the best way.
The best way to add your own PHP functions to Drupal, would be to create your own function library module.
Lets hypothetically call your PHP function library "myfunctionlib", you will need to change that everywhere to reflect your own naming convention.
To create the PHP function library module first create a folder "myfunctionlib".
In that folder create a file called myfunctionlib.module with the following content:
In the same folder create another file called "myfunctionlib.info" with the following content:
The easiest and simplest way to embed video in a drupal post is by just copying and pasting the embed video code into the content you are making.
As with all things drupal, there's also at least one module for this;
A follow-up on Copyright block: a footer with php code in drupal.
I've had some requests to make this a module , so here it is, and there is nothing spectacular about it. It is just an example on how to make a simple block module.
Another question was if you could put drupal copyright footer block in your theme. The answer is yes, but then you would not be able to switch it on / off or change themes as easy.