I've been thinking about this for some time now. Stack Overflow is great for looking up answers to specific (mostly long tail) questions. Sometimes you find bits and pieces of what you need, and put them all together to form a good solution. There are other times where the top answers have security holes or other major issues, or simply answer the question directly without going into other things the person should consider.
While most projects/websites use the same few patterns for authentication, database connections, commenting system, etc. Developers keep recreating the wheel with every new project.
What I would love to help build is a knowledge base that's up to date, with different [patterns/best practices/full examples] to problems using the Stack Exchange system. Each solution would be up/down voted, the same as an answer is now for a question. Users could easily browse all the different patterns prior to starting their project and learn the most recommended solutions (Side benefit of preventing the same questions being asked about simple things on Stack Overflow). The same problem/question can have multiple version for different languages/platforms/technologies. For example the web authentication pattern would have a version for ASP.NET, MVC, PHP, Ruby, etc. using a Database, Active Directory, OpenID, etc.
Also just having a way to see what solutions different projects have implemented would be great. How does the login/authentication system of Stack Overflow differ from Facebook, Google, Digg, Reddit, etc? Which solution has what advantages?
I've thought about starting a site with this idea, but with a full time job and a startup that takes up the rest of my time, I don't have the capacity right now. Because this fits in well with Stack Overflow, I figured this is a good place to get the idea out there.
Is there anything that exists like this already? Does anyone else want this resource to be created?