It was a website for men/women to cheat with one another. It was hacked and they threatened to release all of the information. That's basically the gist of it.
Besides the fact that it's illegal and the hacker can go to jail, there's honestly nothing wrong with it being done. ( note, this isn't sarcasm. Those are literally the only downsides to this )
I'm slightly curious as to what kind of people those two funders of Ashley Madison are since, well, it is pretty sick to encourage people to have an affair. What's next, encouraging people to beat up someone? "Murderers united"? "Special superfancy club for polititians&country leaers who have caused at least one war"?
I see nothing wrong with exposing the users of this site. They knew it was morally wrong from the beginning. I hope each and every person is outted. Serves them right.
JustKiddingNews (one of my favorite YouTube channels) covered it.
https://www.youtube.com/watch?v=w_pfO5ldgCU