If there's one word I want all PocketGamer.biz readers to understand in 2013, it's reciprocity.

As the dictionary definition puts it, this is social psychology refering to when people respond to a positive action with another positive action i.e. rewarding kind actions.

In the case of free-to-play mobile games, it's all about giving your players something small but worthwhile that will increase their enjoyment and hence retention and/or monetisation.

You can read more about it here and here.

Form an orderly queue

Korean publisher Gamevil is certainly keen on reciprocity.

It's just announced that the first 30,000 people to sign up for its new card RPG Kaizin Rumble will receive a starter pack worth $60.

Of course, the value is nominal, particularly in the case of players starting a new game; the $60 value would only come into play if you were a player who was otherwise prepared to spend $60.

Nevertheless, it's an interesting move - if nothing else - in terms of free marketing for the game, which will be out on iOS and Android next week.

You can find out more here