Take google for example. I think they got big at first for 2 big reasons. 1 their landing page was tiny I think the whole thing was maybe 20-50k on first load and 1k on second. It was fast to load. Then on top of that their search results were better. But that tiny front page made the thing look amazing. Remember this was at a time when their nearest competitors had ad laden bloated home pages that took a minute to render. That also helped them keep their costs wildly low at first. As network/hosts/drives/people costs money. They threw all of that out later on though as they took over the ad network. Starting off with 'fast loading ads'.