One evening in April, Carrie* sat down and wrote a suicide note to Zynga, the maker of mobile phone games such as Farmville and Words With Friends.
Carrie had been spending uncontrollably on one of Zynga’s less well-known apps, Wizard of Oz Slots, a game that mimics casino slot machines but with no payout available.
A recovering gambling addict, she had used a national self-exclusion scheme to bar herself from online casinos. There is no such scheme for computer gaming.