chistev
an hour ago
It's a function of title of submission and time of submission.
Sometimes you post at the right time for people to see it and it gathers enough attention to hit the front page. Once it's on the front page, and if it's a really good submission, it can stay there for hours.
But, you really can't tell which submission will be a hit or not. The ones you're certain will blow up can go unnoticed.