After initial success and growth, Zynga wound up having a rough ride on Gaming Boulevard. So it did what anyone would do: It turned onto a new road — Gambler's Alley. After launching online poker and casino games in the United Kingdom on Wednesday, it already seems like the move is paying off. Stockholders responded favorably, sending prices up by as much as 15 percent on the day.

The American company joined forces with online gambling company bwin.party to release online poker, slot machines, blackjack and other games that put real money at stake. Each partner has strengths that they bring to the table — for Zynga, it's social gaming; for bwin.party, that's experience and a hugely successful track record of $32 million in 2012 alone. The partners didn't divulge any plans to bring these betting games Stateside yet, but they did say they were working on "social versions of real money games for players on Facebook and mobile in the UK throughout 2013."

Not that the American market is being ignored. On the contrary, Silicon Valley has been taking notice of the huge potential of online gambling in the U.S. and is likely paying close attention to what U.K.-based gaming firm 888 will do, now that Nevada granted it the state's first online gambling license.

Previously the U.S. federal government had banned online gambling, but changed its mind in 2011, when it gave states the power to legalize it. So far, Nevada, New Jersey and Delaware stepped forward to do that. Little wonder there — these states are home of the countries' leading casinos.