There are apps that offer a Twitter-like feed tailored to a game, apps for group-messaging friends during a game, and apps for booking an athlete to come watch a game with you in person. Now Alex Beckman, who sold one startup to Yahoo (YHOO) in 2013, believes he has a winning horse in GameOn, which combines several functions to compete with all of these products, big and small, including the likes of Twitter, WhatsApp, and ESPN.

GameOn launches today in Apple’s App Store, joining tens of thousands of other sports apps. It is a crowded field of play. But Beckman has big-name help from NFL veterans Joe Montana and Lawyer Milloy, both of whom invested in GameOn’s modest $1.5 million seed round and have an ownership stake in the company. This is far from Montana’s first tech investment, but it is the first for his new fund, Liquid Two. Milloy, who played in the league for 15 years, is a four-time Pro Bowler, a Super Bowl champion, and is now turning his attention to technology.

Today does not mark the birth of GameOn. The service quietly launched a year ago. At that time it was focused on messaging friends during a game—a sort of WhatsApp for sports, tailored to the 2014 FIFA World Cup. The messaging is still part of GameOn, but Beckman and company have completely retooled the app, adding dedicated “huddles” with pro athletes; live score updates; real-time tweets; the ability to earn digital “stickers” (critics may see that as a passé relic from Foursquare and Yelp, but Beckman says they have been a big hit); game highlights; and even Vine videos, which will play natively in GameOn’s app.

If that sounds a bit like “everything and the kitchen sink,” Beckman knows the risks. Many an ambitious mobile app has failed from being over-stuffed.

“That’s the thing I grapple with every day,” he says. “We don’t want to stretch ourselves too thin. I’ve seen my friends do it and I’ve definitely done it myself. But the addition of the athlete portal was probably a six-month process.” After the World Cup last summer, the soccer player Cobi Jones told Beckman he would love if GameOn gave him the ability to talk to fans (and in more than 140 characters at a time). “I thought, ‘Man, me too, but that’s a whole other company, that’s like an athlete dashboard. That’s taking on Twitter,'” Beckman says. “But I started thinking, is there a way we can do it that doesn’t kill us and actually makes sense in the app?” Beckman decided there was, and the GameOn team of eight full-time people has taken each feature slowly.

The overall goal is to be the one-stop place for connecting with people about what’s happening in sports, whether that’s during a game or the next day as you walk into work. Building a single stop for sports news, scores, highlights, and chat means taking on not just Twitter, but a whole host of established players. By showing scores, GameOn is competing with ESPN’s ScoreCenter app. By rolling out athlete-created posts and discussions, GameOn is mimicking Derek Jeter’s web site The Players’ Tribune, where big-name players write personal essays (or their P.R. handlers do) and hold “editor” titles. GameOn is even taking on cable companies, Beckman acknowledges, because, “I want to be the cord-cutting solution on mobile for sports fans.”

While GameOn is catering to all sports, there is one in particular that Beckman says is a surprise opportunity: cricket. Dwayne Bravo, a cricket player in the West Indies, is also a GameOn investor. “There are a lot of Sri Lankan folks who love cricket and know Dwayne Bravo,” says Beckman, “but there’s no really good mobile app that caters to them. For cricket, we can bring the full package to the table and make sure that if you’re from India, living in Silicon Valley, we can give you everything you need.”

For Lawyer Milloy, the 15-season veteran NFL safety, GameOn is a chance to do more than throw some money at a startup. He is not merely an investor, but has taken a day-to-day role at the company. (He even uses a GameOn corporate email address.) Milloy became interested in the industry after watching companies in his hometown of Seattle, like Microsoft and Amazon, grow to become mega-giants. But he wasn’t in a hurry: since retiring in 2010, he hadn’t done much in business until now.

“When I retired I wanted to put all my energy back into my family,” he says. “My wife ripped the Superman cape off me and said, ‘Here’s your new NFL.’ I had four daughters that didn’t really know daddy that well. So my time with them was more important than trying to figure out my next career move. But I always entertained ideas. And with tech, if you find a company you believe in, you can give it some of your time but still have time to be with family. It’s different from a typical 9-5. But you have to be careful, and you learn that it’s okay to say no. In football, you take so much time building up your brand, and then if you get involved with a company that is a little iffy, now you’ve tarnished some of that.”

Milloy met Beckman through a mutual friend that worked at Microsoft. Lest you think he’s just a former athlete dabbling in tech, he says what impressed him about GameOn was, “the U.I. and the functionality. I just looked at it as a consumer. And then as an athlete.”

Yahoo bought Beckman’s company Evntlive, which offered live concert video-streaming, in 2013 for an undisclosed sum. He stayed on for only six months, and found the change in working environment difficult: “It was exciting but frustrating. When I talk to founders [who sell], that seems to be a common feeling.” He was eager to move on to another startup. The genesis of GameOn came when he realized he was switching through nearly 10 different apps during a sports event—checking scores on ESPN, reading news on Fox Sports, communicating directly with friends in WhatsApp, reading public tweets on Twitter.

“Ultimately I want to pull people from Twitter and Snapchat and Instagram that are using those things to follow their favorite athletes,” Beckman says. “So, yeah, it’s a big endeavor.”

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