Online gaming has been taking slow but steady steps to reality in recent weeks. A Justice Department decision opened the door for online poker and lotteries online recently, and a number of bills to regulate poker are in a drawer somewhere on Capitol Hill.

Everyone seems to be angling for a piece of what could be a massive market. Facebook has explored real-money gambling in the U.K. and recently gave a presentation to the lottery industry on how they could use Facebook to connect with players. Zynga (Nasdaq: ZNGA) introduced a poker game before moving to Farmville and may also be interested in the revenue a real-money game could provide.

Table maker Shuffle Master (Nasdaq: SHFL) recently launched an interactive division to offer the company's proprietary games online with a free version available for U.S. players.

And casinos are trying to find the best partnership if poker becomes legal with Wynn Resorts (Nasdaq: WYNN) courting PokerStars before it was shut down, and MGM (NYSE: MGM), Boyd Gaming (NYSE: BYD), and Bwin.Party teaming up as a powerhouse combination.

Projecting the impact
It's unknown exactly how much revenue any gaming company could generate from online poker. But that doesn't mean we can't try to figure out what the impact might be.

Forbes estimated that Full Tilt Poker generated $500 million in revenue and $100 million in profit during 2010. That's just one company in an industry the Financial Times estimated generated $5.9 billion in revenue worldwide in 2008. If we estimate that the MGM partnership could generate at least the revenue of Full Tilt Poker if online poker is legalized, and use the sensitivity analysis below for revenue and EBITDA margins, the impact is pretty big.

Revenue/EBITDA Margin 20% 30% 40%
$500 Million $100 Million $150 Million $200 Million
$1 Billion $200 Million $300 Million $400 Million
$3 Billion $2 Billion $3 Billion $1.2 Billion

If the middle scenario plays out, the MGM partnership could generate $300 million in EBITDA for its owners. For MGM Resorts, its 25% stake means $75 million in EBITDA, a nice addition, but small when compared to its $5.5 billion market cap and $13.1 billion in debt. But for Boyd Gaming, the relative impact would be bigger.

Boyd currently has a $600 million market cap and $2.8 billion in debt. In the past year, the company has generated $331.6 million in EBITDA. An additional $30 million in EBITDA from its 10% stake in the online partnership would be a boon for the company. A rosier scenario could see the company add $120 million in EBITDA if online poker is passed. That's EBITDA growth of 9% to 36% in a business Boyd likely couldn't compete in without joining with bigger names.

Cannibalization of casinos
The argument has been made that online gaming would cannibalize casinos in Las Vegas and around the country. That may be true to some extent, but in my experience, most online players play games with stakes of $0.01/$0.02 to $0.50/$1, games you can't even find in a casino. And poker isn't really a moneymaker for casinos like blackjack or baccarat.

I'm not sure online poker wouldn't be something that wouldn't attract more players to casinos by bringing in new players and offering perks to players.

Surprising winner
It's unknown exactly how Facebook and Zynga would handle online poker or other games, but any impact would be gravy since margins would be high and it would be a new revenue source.

If casino companies dominate the landscape, as I expect, Boyd would get a huge positive impact. The company could basically ride MGM's coattails to market dominance.

So, it's not MGM or Wynn resorts that would be the biggest winners in online gaming. The surprising winners could be Facebook, Zynga, and Boyd Gaming.

Before that happens, the games need to be legalized, something that may fall by the wayside in a presidential election cycle. For the sake of all of the companies mentioned a regulatory solution would be great for their bottom line.

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Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings or follow his CAPS picks at TMFFlushDraw.

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