Casual = Social?

Paintbomb is very close to completion. It is a multiplayer, turn based, casual game on the web. The players will be able to play, blow up (or more precisely, paint) each other, get on highscore lists, etc.

But.

They won't be able to communicate with each other. I started to wonder about this a while ago: Is it a requirement in today's casual multiplayer game to provide the players with the ability of talking to each other? Either by in-game channels, or some attached third party forum? Or, if it is not a requirement, how serious is the players' need of boasting and talking?

Is this something I need to put in right now (even if it delays the start) or is it something I can postpone until the next release?