[esafak]

In the worst case, you'll fail to scale due to technical shortcomings like Friendster and become forgotten while later entrants like Facebook eat your lunch.

There was a time when "being web scale" was a real concern. That's one reason companies like Google make such a big deal about it in their technical interviews. Now most of the hard work has been done and exposed as services so today even an untrained teenager can stand up a web-scale service.