> The salon scheduling example is particularly naïve, because scheduling software would not add much value to either salon owners or customers.

Interestingly, someone told me recently that his sister, who runs a salon, spends a ridiculous amount of money on precisely this: scheduling software! He's a hacker and couldn't quite work out why she would pay $thousands (sic) for some crappy semi-customised calendar when Google Calendar works just fine: in the end it came down to, "because all the other beauty salons use this software".

Not that I'm recommending this particular niche, mind you...