Scripture is abundantly clear about the negative consequences of infidelity.
One such verse states, "Run from sexual sin! No other sin affects the body as this one does. For sexual immorality is a sin against your own body." (1 Cor 6:18)
So, far be it for me to condone a website that profits off of infidelity. Even farther would I pity the people whose identities were hacked in this Ashley Madison scandal. If one is foolish enough to cheat, they would be even more foolish to leave a financial trail.
It is my general belief to always stay safe online. You can never be too careful.
In that light, anyone willing to pay online for immoral services reap what they sow, especially when hacking is such an immanent threat.
I've mentioned this before when my website was one of the many that was hacked by the Russian mob last September. It is imperative to remain secure online.
My own tip is simple: RESPECT YOUR SPOUSE. Never cheat.
At the same time, no one is perfect. Everyone makes mistakes, and we are required to show grace and forgive.
Christ says, "Even if that person wrongs you seven times a day and each time turns again and asks forgiveness, you must forgive." (Luke 17:4)
That leaked list can turn into quite a slippery slope. One could easily become obsessed with finding a familiar name of it. I won't even look at it. I would recommend you do not do the same. The only way to fight these hackers is to show a refusal to support them.