Yup - Notes, and Itsy (my Twitter client). Although the potential horror of it keeping the crash occurring when you reopen the app doesn't seem to be the case for me. Notes did lock up a second time when I selected the note in question and tried to carry on typing after the ///.
Simply cured by reopening it, and deleting the 'F' from the front.
A curious bug, certainly, and not one that's consistent from install to install from the sounds of things.

It depends on the version of NSTextFields installed, and also whether "data detectors" is enabled on your machine. Apparently. I have no idea what that means, just repeating a post from Hacker News lol.

So this utterly horrible bug can be mitigated by the tremendously complex procedure of going to the Apple menu and selecting 'Software Update...'? Oh my, I can tell why it's all over the internet.

I think it effects the most recent version, hence all the noise. Updating right now wouldn't solve it.

It looks like a trivial problem to solve though, just a few bytes to re-write, so an update should be out soon.

Well, I'm running the most up to date version of ML, and I've managed to get some apps to lock up with this bug.
It's not exactly mission critical, and like JJ, I can't imagine it'll be terribly difficult to patch.

I think people are talking about it so much just because it's a bit unusual and kinda funny. No one is claiming it's the end of the world. It's not even a real security threat, except in so far that someone might crash your IM. That mostly depends on having mean friends though