Do's and Don't
Use Open Source Judiciously
We all know the benefits of using open source, but what are the pitfalls? If you have been asked to build a professional, production-ready, mission-critical, customer-facing application, you probably don't want to go bleeding edge.
You need to ask yourself if the project is ready for prime-time. Don't be fooled by a glossy, over-hyped project page. Dig deep. Find out
how many people are really using the project. Look at the mailing list archives. Is it active enough? Is is full of unanswered questions? Check out the source from subversion. Review the check-in history. If time permits, read the code.
For short-timeframe, mission-critical projects, I use what I call The Book Test. Any project for which an O'Reilly book has been written has been vetted and tested to my satisfaction. If three or more books on the subject have been written and are available from your local bookstore, you can bet that the technology is ubiquitous. Tried and true open source projects include Linux, Apache web server, Python, PHP, and Ruby. This litmus test will eliminate a majority of the projects you find on source forge, so this shouldn't be your only test. But it's a good place to start.