I also saw the message icon on CMC yesterday, and I think it's very useful to be able to share opinions about cryptocurrency with people we don't know yet and can also suggest various inputs for the progress of the CMC site itself.
Well, I saw it but you need to signup first before you can join their conversation. It only required a Gmail address and of course a strong password on it.Well, I hope this is not going to misuse from other members.
I have a strong feeling that perhaps this maybe can use in a hype project, --by spamming the name of the coin in community will give attract to the reader and perhaps will cause hype. Indeed, that is really to the traders that seeking the right information [I hope so] that you can communicate with each other.
. 
Anyway, it is not compulsory to join their chat but somehow some users will feel that they are left behind if they will not join. I think, it is only for those users who are interested to enjoy this feature so if they will use their main email account, it is their choice. So expect also to receive some "spam emails" from them. 
