Key words being 'bay area', which is in no way representative of the market Square needs.

Another challenge for Square is that their core merchants are mom & pop coffee shops or like you said, food trucks - not particularly lucrative segments.

Square's POS can never compete with full-service POS (Aloha, Micros), and even in the quick-service market there is increasing competition (Clover POS, Revel etc). That's why they've moved into payroll, HR, time-tracking, albeit the $5 per employee is ridiculously expensive for SMB's.

Square will obviously have to grow more, but the reason I think they have a future is they're getting merchants who didn't take cards to take them, easily and cheaply. My family is not on the coast and there's still a lot of places that don't take cards for whom square should be a really good solution. Then they can do the classic microsoft strategy: start with the smallest/cheapest and relentlessly move upmarket. Will they ever be the solution for Safeway with hundreds of stores and a very complex discounting system? Probably not. But there's a lot of smaller businesses. Small to medium restaurants should be a key target customer.

Here in Denver I see it all the time. I actually don't really notice it (a problem for them as so many competitors directly cloned them)... until that email receipt arrives.

It's not ubiquitous here, but it's certainly common.