Today Apple released iOS 6.1.3. Within the release notes the company explained that jailbreak development team evad3rs discovered four of six exploits fixed with the latest update.
evasi0n became the most popular jailbreak in iOS history. It reached 7 million downloads within a week and doubled that by the end of the month. For now, the latest update patches those flaws, and renders the jailbreak useless. Still, one of the creators of the jailbreak, David Wang, says that there may be enough exploits remaining to create a new jailbreak tool.
Sometimes, I think Apple appreciates the jailbreak developers to some degree. They find tons of exploits, and Apple patches them, creating a more secure iOS. Perhaps. Just a thought.