By being a user, you are acknowledging that you are a member of the community. You can also understand (by merely looking at source code, how concepts/theory are implemented. You can also acquire the most sought skill of "source code comprehension" by having access to volumes of code written by vastly different communities of developers.

The Industry (not just the software one, even the electronics one) converges towards standards, after all we like stereotypism, (do we?). So if you're out there to learn tcp/ip (duh - read stevens says someone), or *STOP IT* .... read the implementation, not [just] the RFC (nobody's just these days.) Point is how will you read the implementation if it was hiding away from you, there goes the "Open" funda.