Back story:

My best friend is a self-taught coder for a community art site, written in PHP. Some time ago he mentioned he wanted to make the source code of the site public, to which my response was total horror - surely it was going to be full of security holes waiting to be found, and it was going to lead to hacking and errors on a huge scale. He never ended up doing it.

Current story:

I'm starting development of a community website built in Rails, and for ease of use I was going to use Github for version control. Then I realized it was pretty much exactly the same thing as my friend making his source code public - which made me stop and think.

Would you make your website's completely-custom source code public? Or is this a case of open source gone too far?

(note: I don't think this applies to people who run things like Wordpress. Or does it?)