Question: How should I approach open source software development? More specifically, should I start from scratch on an idea? or contribute to a similar existing project?

Answer: I suggest you to start with an existing open source project. you can find very good open source projects at www.sourceforge.net   if you find a project you are interested, just send email to the project admin they can add you in. Of course, if you have a very good idea, you can create your own sourceforge project, and share it with the rest of the world.
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