I think part of it, is that they had a fun product, when there was no real competition from things like youtube(+5 years), flash games(+7 years), hulu(+9 years)

I think part of it, is that they had a fun product, when there was no real competition from things like youtube(+5 years), flash games(+7 years), hulu(+9 years), decent social networks(+3 years myspace, +4 years facebook) And the product itself, led them to pretty much be able to signup anyone who stumbled on their website.