At 400 you get to downvote.

At 401 you get to apologize for accidentally downvoting someone.

At 419 you get lucrative business opportunities.

At 420 you get baked.

At 451 you get [deleted].

At 777 you get lucky.

At 1337 "they" teach you the Secret Handshake Deal Protocol.

At 1999 you have to update a million lines of COBOL in order to advance.

At 2010 you get to complain that Hacker News is turning into Reddit.

At 2600 you get to make free long distance calls.

At 3003 you get your TI-83 taken away and returned to you at the end of class.

At 4352 you get to get to post a jokey self-referential comment without anybody complaining that Hacker News is turning into Reddit.