[6ren]

Thanks: improvement; brand; free/ad supported. Looking at your site, looks like massive networks effects too, as people contribute quizzes that others can use (maybe it's fair to include viral word-of-mouth as a competitive advantage too, from quiz sharing, though it's usually classified as marketing).

Some of these competitive advantages do seem to serendipitously fall out of helping people after all: making a better product for them; letting them know about it.

Perhaps these naturally fall out of trying to solve a problem or address a need (especialy "being your own customer" with that problem/need). There's always ways to improve it, because most needs/problems are never perfectly solved - which is good for competitive advantage. I'm in the opposite place, of developing a solution - it's beginning to seem like a fundamentally difficult way to go.