Is it? With everyone talking about it here how important it is, I get the feeling it is over hyped. There is also not a lot or maybe actually no proof at all these sites became popular because of design. They threw massive amounts of VC money into marketing and networking and ads etc. And next to that they went viral (probably because of the massive amounts of vc money and people in influencer circles egging eachother on, for which you can find traces on HN and reddit easily): would be great to see some actual references how you came to say with such certainty this is 'because of design'.