As someone who uses other people's payment systems, Square makes me happy. It's a product that respects the users.

But too bad we don't actually make them money.

Really complex retailers with broad product lines, like supermarkets and big box retailers, will continue with highly customized in-house solutions. But for retailers with only dozens or hundreds rather than thousands of products, and limited budget to buy fancy solutions, it's a godsend.

And, because the customers are making a major, high-risk, customer-facing commitment, they're going to be very sticky, very unlikely to switch. Basically, Square is entering a market where the established players are too slow and coarse-grained to reach a lot of potential customers, and then they'll have a terrific barrier to entry. That sounds like a good deal to me, from an investment point of view.

Some citations would be nice