This is a great post by Pierre Raynaud-Richard at Facebook about their Engineering Culture; specifically Code Ownership. There are a lot of important ideas in here and I encourage you to read it thoroughly.

Here's one of my favorite sections:

The culture of the "code expert" results in a world of sclerosis and stagnation where really bad things can occur. Here are just two examples:

• The ideas of the expert are no longer challenged. The gap in knowledge and “expertise” only grows with time, and the title and position of “expert” can be used unfairly to win arguments.
• Innovation can be crippled, as new ideas are expected to come from the individuals who are least likely to generate truly new ideas (because they’re so deeply involved in and biased by the details of the current design and implementation), and these individuals are given implicit or explicit authority to dwarf disruptive ideas from the outside.
• The official role and recognition of "code experts" implicitly dampen and narrow the creative contribution of new engineers. It is easier and more natural for them to just follow the lead of the “experts” instead of diving in and forming their own opinions and ideas. Over time, this may result in a “lean back” syndrome, where people feel they should care only about their own narrow piece of the puzzle.

Some organizations attempt to solve these issues by putting different people in charge of generating disruptive ideas (like architects or product managers), while component experts are in charge of the implementation. This only displaces the bottleneck of innovation and formalizes it further, with even worse results if both parties don’t work well together.