You could try to construct an argument that what you did was reasonable given the circumstances, but from your brief description, it's pretty clear you overstepped the line.
On the positive side - threats of lawsuits are enormously more common that actual lawsuits. Having someone say "pay up or I'll file a lawsuit" is a long way short of "being sued". It's entirely possible he'll be no more competent at engaging legal representation and taking this to lawsuit stage than he was at securing his website.
Don't antagonise him (any more, you've already done enough there). (If it's true,) make it clear to him that suing for large amounts of money isn't going to be useful - since you don't have assets to cover it.
Bottom line - the legal system is _exactly_ the right tool for this job. You did something that's not just "childish", but clearly wrong (breaking into the site), and exacerbated it by then writing the extension and publicising it to your stolen user email list (surely there were great big alarm bells going off in your head when you decided to do that?).
If you're lucky, you're about to learn a lesson in how easy it is to almost get in big trouble. If you're not lucky you are about to learn about accepting responsibility for your actions like an adult.
You could try to construct an argument that what you did was reasonable given the circumstances, but from your brief description, it's pretty clear you overstepped the line.
On the positive side - threats of lawsuits are enormously more common that actual lawsuits. Having someone say "pay up or I'll file a lawsuit" is a long way short of "being sued". It's entirely possible he'll be no more competent at engaging legal representation and taking this to lawsuit stage than he was at securing his website.
Don't antagonise him (any more, you've already done enough there). (If it's true,) make it clear to him that suing for large amounts of money isn't going to be useful - since you don't have assets to cover it.
Bottom line - the legal system is _exactly_ the right tool for this job. You did something that's not just "childish", but clearly wrong (breaking into the site), and exacerbated it by then writing the extension and publicising it to your stolen user email list (surely there were great big alarm bells going off in your head when you decided to do that?).
If you're lucky, you're about to learn a lesson in how easy it is to almost get in big trouble. If you're not lucky you are about to learn about accepting responsibility for your actions like an adult.