The monetization plan is already there (in details), it's just that we don't want to spend time coding it if we don't have the required traction. Hope this makes more sense?
We did a group chat product at groupflier.com and got great traction on the free version but the SMS costs killed us and we had to switch to a paid model. Happy to trade PM on our experiences if you are interested and have a blog about it at:
http://gcrawshaw.posterous.com/group-texting-is-a-telco-game