@QGil:

A little bit about motivation:
Humans (when not forced) will not work for free. So, in order to get any development going, your developers have to get motivation. There are just two major sources of motivation:

• Material (money, toys, food, free travel opportunities, etc. with money easily leading the list)
• Psychological (seeing results of your work everywhere, crowds of people coming to you for advice, groupies sending you flower baskets, etc.)

Now, if we get the first motivation source off the table, we are left with psychological motivation. That is what makes open source developers do their work for free. The main problem with psychological motivation is that it is elusive. Very few people can work on psychological motivation alone for long periods of time: at some point, you will still have to pay them. Aside from this, here is a few hints how you can kill all psychological motivation in your developer community:

• Let developers work on their projects but do not promote the results of their work in official products, so that developers feel like you do not care what they are doing. This is a sure way to kill all community development.
• Force strict procedural guidelines on your developer community. Make developers sign NDAs, adhere to style guides, use the same centralized version control system, request digital certificates, go through extra loops just to make their stuff available to the users. See Symbian development model for hints on how you can do this.
• Herd developers into large groups working on big projects. This serves two purposes: 1) it makes every individual's contribution look small and insigificant and 2) causes your developers to endlessly argue about technical details with the losing side quitting in disgust.

PS: Calls like "let everyone just select a project and start working on it" do nothing to motivate your developers and thus will not produce any meaningful results. But you probably know it by now.