If you really want to clone 9gag, you don’t need to actually log any votes. It’s a fake community run by the admins. Here, read: 9GAG "Repost Machine" Explained : 9gag
They blindly copy all popular content from reddit, tumblr, funnyjunk, etc, remove watermarks, use a random fake user account to submit it, then alter the submission date to make it seem like it was posted there first, and push it directly to the front page, then censor any comments that might mention the original source or any rival website. Very scummy stuff.