It also allows for joining servers, and shows the IP then.

The reality of the matter is that even if you absolutely infuriate someone it is unlikely they will hack you; not that this means you should. Besides, getting your IP is not enough to hack someone. If it was, the world would be in a lot more trouble. As long as you do not accept suspicious files, it should be fine.

There is about equal chance of getting hacked when the list server is down as when it is not. If someone is going to hack you, they are dedicated to doing so and will find out your IP, whether they use XJJ2 or not. My point is, not posting your IP here will not do much more harm as the chance of a random hacking is low.

Besides, if you have updated patches and a good antivirus program and/or firewall, it is even less likely. No need to worry about it.

~ Traft