Reddit:- You Google Reddit and your first result is Reddit.com. You click the link and are presented with the front page. You from scroll from a few hours and end up signing up and staying.
I don't think this is the path most people take to becoming new Reddit users.
I think most people end up using new social media sites because they get linked to content already on a given site that they like. This could be from friends sharing links, or through Google results from the site.