Millions of Ashley Madison customers had their private information leaked in a hack of the website, and blackmailers are making big money utilizing the data.
The Register reports that researchers have really been able to monitor payments online that were sent using the virtual money bitcoin.

Cloudmark analyst Toshiro Nishimura looked into bitcoin addresses which were contained in e-mails sent to targets of the Ashley Madison hack. Blackmailers have been contacting users of the website threatening to send it to their relatives or co-workers, or assuring to remove their information on the web.

Knowing a bitcoin address then it is not impossible to monitor payments sent to it over the web. He located 67 distinct trades which suggest that Ashley Madison customers paid around $6,400 to scammers., and managed to monitor payments to the addresses

During the press conference cops revealed an instance of one of the blackmail e-mails received by an Ashley Madison customer.