It was a user with a grudge that was banned from the service. They attempted to use a number of online point and click tools to attack the site, until I eventually banned their IP address, and then talked with them and threatened legal action.
This whole thread people discuss technical mitigations, and I'm thinking "man, this is such a clear case where a bit of law and the tiniest amount of civil damages totally would fix the situation, as long as the attacking person lives in a country with a level of rule of law." What a waste of resources trying to make something impossible, rather than just illegal. (I was thinking mostly of the anticompetitive acts and the title.)
Your comment actually shows a clear example, of how actually threatening legal action makes someone come to their senses, whereas any level of technical measures just gamified the situation.
This is just a case where we can collectively enter an arms race for technical solutions, or just use a bit of law and live in a sane society where this isn't on the competitive menu.
