Scott makes a great distinction between Open Source code and Source Out in the open.
Public Does Not Equal Open Source
I wanted to add to the discussion by pointing out two things. Often people make the mistake of assuming that any code posted on someone’s blog or in Google Groups is either open source or public domain. This is not necessarily true.
While it might be the intent of the author to make code published in a blog or Google Groups open to the public domain or freely distributed as open source, as the consumer of the code we cannot assume this to be the case. If the author does not state the license under which the code is available (either by just saying so or by referencing a license), then the author owns the exclusive copyright (assuming he or she wrote the code etc...).
I try to make a habit of asking permission from authors of useful code when I cannot find any license information on their blog. My blog is licensed under the Creative Commons Attribution license, so you can assume that any code snippets I post are licensed in the same way unless I specifically state otherwise.
I wrote on this topic in my Developer’s Guide to Open Source Software Licensing, which I know you read because developers just love reading up on legal topics.
The second thing I wanted to add to the discussion, and maybe I am way late on this, but I just recently learned about koders.com, an open source search engine.
It is a search engine that indexes various open source repositories and allows you to conduct searches through the source code. For each piece of code it returns, it presents the language, the location, the source, and the license.
This is an interesting way to take a look at open source code, though not without its quirks. Finding a method that you need can be difficult since the semantics of what code does and naming conventions are so different from project to project. But over time, this may become a useful tool.