Mike Shaver and myself have been recently spending some time explaining why Mozilla (and mozillians) cares about the Open Web. There are many reasons for this, but I'll focus on the fact that you can view the source of Web pages, which is a great way to learn. This may sound hypothetical until you read this quote from Ben Goodger, explaining how he got involved in the Web, down in New Zealand:
I didn't have Internet access at home because it was expensive and we didn't have a lot of money. I lived with my mother, who works as an accountant. I would occasionally be able to get Internet access at her work. I was around 17 when I thought, "Maybe I'll try building a Web site." It seemed like it wasn't too difficult. I could just read stuff. I would build it at home and then go into work with her when she had to work late and I would sit there at a computer and upload it.
Ben has been the lead developer for Firefox 1.0 and is now with Google (but not actively contributing to Mozilla anymore).
I think Ben's quote is a great example of the power of the Open Web. It's Open. People can learn from others. People can become empowered by what they learn. And the more they publish on the Web, the more it becomes valuable for everybody, and the more it's likely for people to be exposed to it to eventually contribute, as the web snowballs. I find this extremely compelling in favor of the Open Web, as opposed to proprietary technologies which source code is not available to the users to view.