Casinos in Las Vegas have been marketing through social media for some time now, mostly via Facebook and Twitter. Recently, however, two Las Vegas-based casino companies have taken their investment in social media to another level with Facebook applications.

Facebook allows third-party developers to create applications, or apps, that users can access through their Facebook pages. Social games are some of the most popular apps available. Unlike sites that offer play-for-free (or play-for-cash), these games require no download and can be played in a standard Web browser. By definition, they allow players to invite friends to join games and compete in friendly competitions.

Harrah’s Entertainment, through its Interactive Entertainment subsidiary, has partnered with Playdom—a developer with more than 130 million installed social games on Facebook, MySpace, Hi5 and the iPhone—to offer a World Series of Poker Facebook game.

According to Craig Abrahams, vice president of Harrah’s Interactive Entertainment, the social media space was “simply too large to ignore.” With more than 30 million people playing poker on Facebook, it made sense to introduce the WSOP brand to the social network.

Instead of building its own poker game in-house, Harrah’s chose to join forces with Playdom because with its 40 million users and an existing poker game, called Poker Palace, it provided the best opportunity to make a big, quick impact.

Shortly before the announcement of the WSOP launch, Disney acquired Playdom for about $763 million. There’s actually some existing synergy between Disney and the WSOP: Disney subsidiary ESPN broadcasts the WSOP and has been a partner in the tournament’s rise in popularity.

Moving into social games, Abrahams says, is a way to keep that popularity expanding.

“We always wanted to have WSOP experiences available globally on digital platforms,” he says. “We’ve had the top iPhone game and console game, and social networks are the next platform.”

The global nature of these platforms particularly intrigues Harrah’s. “With 50 percent of users coming from outside the United States,” Abrahams says, “this gives us a chance to expand internationally and a scalable way to expand our brand.”

The Golden Nugget is taking a different approach. Instead of branding casino games, it’s putting its name on a game that lets players build and nurture a virtual casino. One of many simulation games that let players dabble in creating farms, restaurants and even Mafia families, the Golden Nugget Vegas Casino game allows Facebookers to play casino manager, starting off with a few slot machines and, if things go well, eventually presiding over a thriving casino.

The game was developed by Last Legion, a Santa Monica, Calif.-based company that has produced a range of games. Amy Chasey, the Golden Nugget’s vice president of marketing, sees the game as a way to expand the property’s presence.

“We already have our own Facebook page and Twitter feeds, but this gives us a chance to get in front of people who might know who we are but haven’t been here for a while, so we can introduce the changes we’ve made, like the [500-room, 25-story] Rush Tower.”

For now, the game is in beta mode, but Chasey says we should look for more features soon.

“Right now it’s casino-oriented, but we’ve been talking about letting players build the entire resort, adding a hotel and restaurants,” she says. “There’s a great opportunity to cross-market with our Landry’s restaurants. We want to keep on expanding to give the game a long shelf life.”

In the end, it’s likely we’ll see social games follow the same path as console titles: Although initially unbranded titles dominated the market, titles that took advantage of brand names later pushed them out. The same thing happened with slot machines. Once, slots such as “Double Diamonds” and “Hot Sevens” were the most popular games on the casino floor. Then, branded games such as “Wheel of Fortune” and “I Dream of Jeannie” found a place next to them, and today games spun off from movies and other television shows are popular.

So don’t be surprised if you’re soon able to virtually gamble at or manage your favorite casino anytime soon.