"10 years ago, sports betting was illegal in most of the country... now that it's on everybody's phone, it really has become kind of omnipresent in the culture in a way that I think a lot of people find startling." The rapid legalization and cultural normalization of mobile sports betting, combined with massive events like March Madness (which has a projected $3 billion betting handle), will drive exponential user growth and revenue for the dominant sportsbook operators. LONG. The frictionless nature of mobile betting apps is creating a massive, highly engaged user base that consistently generates profits for the house. Increased regulatory scrutiny or crackdowns on advertising due to rising gambling addiction rates could severely impact user acquisition and revenue growth.