Nimbuzz: a new cell phone ettiquete coming?

Stumbled upon Nimbuzz, that brings instant messaging (IM) and mobile phones closer. Beyond its skype-like features (international calls at local costs), or its group calls, what I find specially interesting is their Buzz alert, a "conscious unsuccessful call attempt" that gives official status to lost-calls, one of the most used resources for any one scared about mobile phone rates in my corner of the world.

My most used features of IM is the ability to have the very short conversation "-ok if I call now? -ok/5 minutes, pls". Bringing that to mobile phones, much more intrusive than land lines, can only be a good thing.

Another thing that makes me consider looking into Nimbuzz is that maybe it provides a decent IM client. Yesterday I used for the first time Yahoo! Messenger from my cell phone, and the experience was just awful (e.g. once you read a message, it is gone forever). Having a semi decent IM client in my phone could be useful from time to time.