With a record 8,773 players having entered the World Series of Poker this year, the event continues to be a big success for

Harrah's Entertainment

( HET), which held the tournament at its Rio casino in Las Vegas.

Not only did the world's biggest poker tournament make the Rio the place to play poker on the Las Vegas Strip over the past month and a half, it also helped the property dominate all table game usage in Vegas.

The Rio had a 30.9% share of the Las Vegas Strip poker game usage during the June 25 to Aug. 11 period of the WSOP tournament. That's up from 22.3% the prior year, according to Majestic Research, an independent firm that uses proprietary data to forecast company revenue.

Excluding poker, Rio's table game usage increased 4% during the tournament, compared with a 3% decline for the rest of the Strip properties; this suggests that the Rio stole customers from other properties.

"In general we were very pleased with the incremental increase of traffic from the World Series of Poker," says David Strow, a Harrah's spokesman. "We saw more players and more spectators than any other poker tournament in history."

Strow declined to give specific numbers, since the company has yet to report third-quarter results.

Though poker is not necessarily a big revenue driver, casino operators have sought to take advantage of the game's growing popularity in recent years. Gone are the days when casinos shut down their poker rooms to make way for more slot machines and blackjack tables.

"The reason why poker is important to a casino is that it brings traffic to the casino and players who end up playing other types of casino games, namely other table games," says Matthew Jacob, a gaming analyst with Majestic Research.

Harrah's paid $42.7 million in 2004 for the rights to the World Series of Poker brand and use of the Horseshoe brand in Nevada.

Besides the annual Vegas main event, the WSOP also hosts circuit tournaments throughout the country that boost Harrah's properties in South Lake Tahoe, Calif., Atlantic City, N.J., Mississippi and other markets.

While the WSOP is a big boost for Harrah's Rio casino in the summer, that property and other Harrah's poker rooms lag

MGM Mirage's

(MGM) - Get Report

Bellagio casino for the rest of the year, according to data from Majestic Research.

Up until the World Series started, the Rio had only a 3% share of the Strip's poker usage. During the same period, the leading poker room was Bellagio, a perennial favorite, which captured 14% of the poker usage on the Strip. Next up were the

Wynn

(WYNN) - Get Report

casino and another MGM property, the Mirage casino, which each captured about 11% of the poker action.

Caesars Palace, which Harrah's also owns, held 8% of the poker usage in that same time frame. Late last year, the property opened an expanded poker room, transforming it into one of the largest in the city.

"The poker room at Caesars is extremely competitive with Bellagio," says Strow, the Harrah's spokesman. "Obviously word of mouth needs to build up."

Bellagio's poker room draw has been helped by the fact that it's the clear favorite of the pros. It plays host to the Big Game, the biggest regular high-stakes cash poker game in town, where pros such as Doyle Brunson and Daniel Negreanu trade hundreds of thousands of dollars on any given night.

Wynn was able to build up its poker room when it opened last year by hiring Negreanu as the casino's poker ambassador, but Negreanu ended up leaving the gig so he could play elsewhere, especially in the Big Game.

Strow says Caesars has not hired a poker ambassador but does have an advisory council of poker professionals, such as pro Howard Lederer, who provide input but are not held under exclusive agreements.

Of course, even if Harrah's poker rooms aren't the biggest draws in Vegas, it might not matter. The Rio and the flagship Harrah's property are the most efficient of all Strip casinos because of the company's stellar marketing program, Jacob says.

One of the metrics Majestic Research tracks is a property's share of market game usage divided by the property's share of market gaming positions. For the entire Las Vegas market, the metric has to equal 100%.

Harrah's Las Vegas and the Rio have recently been operating at 140% to 150%, meaning the properties are capturing a higher percentage of overall gaming in the market without an accompanying larger share of gambling tables or slot machines.

That's impressive considering that the Harrah's site is older and that the Rio is not well-located, away from the center of the Strip.

Recently, the casinos Harrah's purchased from Caesars -- such as Caesars Palace -- have jumped from 100% to a range of 110% to 115% in the Majestic metric as Harrah's incorporates its total rewards marketing plans at those properties, Jacob says.

In comparison, the Wynn casino and the Bellagio, which are considered two of the most top-notch casinos on the Strip, operate closer to 100%.

"You would think Bellagio or Wynn would do a better job," Jacob says.

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