[gametheory]

and the biggest one of all, the inability to downvote.

[niyazpk]

You can downvote once you pass a karma threshold. But don't worry about it too much; hopefully you will not be using it much here.

[epochwolf]

You can down vote comments once you get 201 karma. Articles can't be downvoted. (And don't you dare use the flag as a downvote, that's a no no ;)