Well I found yahoo search that gives much accurate backlink figure. As far as popularity of any particular website concern it just based on the mass visitors traffic that trust and buy its information, services and products. They got naturally backlinks which are enough to maintain their Pr i think search engine, pr's dose matter at the start of new website but when it becomes a brand these things doesn’t matter enough.

Today how many people don’t know about google? Its answer will make you understand enough

Yes marketability of the domain also matters. If it is a brandable domain name on which this site is running then its brand name should be a solid one.

Backlinks are just a way to get PR, Good SERP's and eventually the exposure that the site needs to become an established site.

thats true Nameslot. but i think a natural clickable idea can make the diffirence you can see 'youtube'