Since your product seems to be coded in python the source is kind of "open-source" already isn't it? Also its not the commercial competitors that will screw you, the real danger is if someone will find your project interesting, disagree with some small thing, fork it and release it as a new free open-source product, get a few more people interested to contribute so you as a one-man-shop can't keep up and thereby replace your product with a _real_ open-source product. Heck, I'm almost tempted to copy your repository, do some simple query-replace and put it up on google code just to make a statement and see how you turn-coat and will start complain and whine in your next blog post.
I could very well strip all comments and distribute just pyc files. Those can be reversed to commentless source, but it's not exactly as useful as the original source code. And honestly, anyone could clone the product just fine even without the source code.
If you really want to fork the project, go for it. That's within your rights as per the GPL license. Just as long as you continue to abide by the license yourself. If your fork turns out to be better than my code, and more people end up using it, then you probably deserve any users you "take away" from me.
If, on the other hand, you're just forking the code to be surly, then that's within your rights too.
