Just of the top of my head I could say Paypal (when they started out) and AirBnb operate in legal grey areas.
And, Indiana also requires licensure for money transmission. IC 28-8-4-20 (a) A person may not engage in the business of money transmission without a license required by this chapter.
Therefore, Paypal is illegal in Indiana. But the only reason why I think they haven't been 'busted' is because nobody has complained yet to the appropriate Indiana authorities.
edit: I've been heavily criticised by OstiaAntica for this comment for being "anti-hacker". But I'm simply stating facts, and an opinion as why I think why. http://news.ycombinator.com/item?id=3088836