They probably auto-flag duplicates and known spam. Whenever I look at the "new" page, it seems like a firehose of posts. I'd imagine there's luck involved with

They probably auto-flag duplicates and known spam. Whenever I look at the "new" page, it seems like a firehose of posts. I'd imagine there's luck involved with how many people happen to visit the "New" page before a post is pushed into the abyss. I'd also imagine there's a certain time-frame where a post is more likely to catch traction.