It looks like this area is getting a bit behind. I don't think that many people still use ICQ and use of AIM messenger has likely decreased as well. Personally, I've dropped those as well as Yahoo.

I only use Skype (Splaktar) and Google Talk/Google+ now. Of course this is even seeing some change atm now that Microsoft bought Skype and are in the process of integrating it with Live accounts (plus the existing integration with Facebook accounts). So far it does look like they are keeping the separate Skype accounts around, for now.

I don't know how much these messaging features under the avatars are used. But it might be helpful to add Skype/Google to the list if it isn't a huge task.