In pro hockey, season-ticket holders are as important as ice because they help pay the bills.

There's refrigeration to keep the ice from melting. For season-ticket holders, there's E Group, a Minneapolis firm that uses e-mail and Web-based incentive programs to keep Minnesota Wild fans coming back.

"You can think of what we do as a loyalty program," said John Lemke, E Group's director of loyalty marketing. "We give customers points for fan behavior the team wants to reinforce."

The "good" fan behavior E Group wants to encourage includes renewing season ticket packages, renewing early, renewing for multiple seasons at once and even paying by check, which eliminates credit card fees for the team. In the future, such behavior will be expanded to include rewards for perfect attendance at games and arriving early, which boosts sales at concession stands.

As with many such marketing programs, Wild season-ticket holders accumulate points, called "Wild Rewards," that they can trade in for goods and events that range from bobblehead dolls to meeting Wild players to rides on the Zamboni. In addition, there are website auctions where fans bid their points to win big-ticket items such as traveling to an away game on the team jet.

"We engage people on all the touch-points they might potentially have with a team," Lemke said.

The E Group service, called the eFan platform, is invisible to fans, a technique that marketers call "white labeling." The promotional e-mails appear to come from the team and the website for season-ticket holders is indistinguishable from the team website to which it is linked. Even E Group's connection to Ticketmaster, which helps season-ticket holders exchange tickets for games they can't attend for additional tickets to another game, looks as if it is a sports team service.

"The only people who know about eFan are the sports teams," Lemke said.

Minnesota Wild officials say the E Group incentive program is working.

"We've certainly seen a direct correlation between increased retention of season-ticket ­holders and the people who are engaged with the E Group program," said Maria Troje, the Wild's senior director of fan relations. "Right now we're using it as a retention program, but we're going to use it to attract fans who are not season-ticket holders."

E Group says it's ready to expand the service to serve other groups of ticket buyers.

"We can go after the mass market, which includes people who buy half a season worth of games, or a five-pack of tickets and even the casual fan who occasionally buys single-game tickets," Lemke said. Those once-in-a-while ticket buyers will be able to accumulate points by using social media to follow a team, "check in" at games or talk about games on Twitter.

Lemke said E Group's work with the Wild has resulted in agreements with other pro sports teams, including MLB's Cleveland Indians and Miami Marlins, the NBA's Los Angeles Clippers, Washington Wizards and Brooklyn Nets and the NHL's Los Angeles Kings, Nashville Predators and Winnipeg Jets.

The Cleveland Indians, who have used E Group's promotions since 2012, say they think it helps keep season-ticket holders happy.

"This will be our first full season with the rewards, so it's a bit early to tell what impact it's had on season-ticket holder renewals," said Steven Shin, a sales analyst with the Cleveland team. "But overall, we're happy with E Group. They offer many types of rewards, including watching batting practice from the field, throwing out the first pitch or using one of our suites for a game."

Lars Ranger, the E Group accounts director, says the service can be used both to retain existing ticket buyers and attract new ones. Satisfied fans "talk about the experience they had and that's a good way to get new customers," he said.

Ranger added that the digital loyalty program has produced quantifiable results for the Minnesota Wild, though he said he couldn't provide specific data.