One thought might be to share the information you gave them as widely as possible. For example, I'd be interested in reading that ten page write-up you mentioned.

Similarly, since your code was open sourced, you should be allowed to redistribute derivative works. Meaning: fight back. Create modules and what not to allow the open source community to do those very things that they're not permitting. Oh, sure, you'll need to build a new community, find new servers, and so forth. Nevertheless, if you're angry enough to take effective action, it may be possible to put them out of business. Barring that happy circumstance, you can at least dent their success in that business to some degree.

If you take that latter approach, I'd be sure to change certain things subtly, just in case their administrators and code monkeys weren't listening as carefully as they should have been during your training sessions. Make them work to participate in any new projects along these lines. Confuse 'em even. That way, mebbe they'll have to reconsider their tactics.

Remember: Resistance is not futile.

--f