They might not be themselves differentiators, but they are indicators of a differentiated understanding of how to design a good Q & A site that elicits high quality content from high quality contributers.
Technology is no longer the only differentiator. We've moved far enough "up the stack" that there are lots of ways to differentiate in consumer internet beyond better algorithms.
Do Craigslist, Facebook, or Twitter have anything that's, in your opinion, "differentiated"?
I think Craiglist and Twitter had first mover advantage.
Facebook definitely started with the network effect. It was far technically inferior to Myspace and Friendster when I first signed up.
I only joined because of the exclusive feel which soon changed when they branched out. Many of my colleagues and I have said we never would have made a Facebook account if it was public like it is now.
