I apologize if I get anything wrong. I read the entirety of this thread in one sitting, still trying to absorb most into my head.
First off, about the client-side list:
1) It would make sense to list only people that you\'ve met (i.e. Have gotten a name from). It would be a big waste of space to, instead, have a list of everyone registered, not to mention your list would need to be reupdated everytime you log into the world (creating a longer amount of login time). If said list only has the people you\'ve been introduced to, it should also have a line that nullifies every other player. (hope that makes sense, it\'s about 3:30 AM. :-P)
2) Hacking would be essentially unneccessary in all forms with this idea (1). Since you have a list of people you\'ve met and their names, the only thing you could do is rename them, which would do nothing but create an alias to only you. (since it\'s client-side, the effect would only be on the clients...side. Thusly, no one else would see the effects of the change but the client.) This might actually be seen as an advantage for some people. Say you don\'t like someones name, but they don\'t want to change it? Just go into your client-side stored \"Introduction List\" and rename them. Only you will see the rename and hopefully you renamed it to something that you\'ll remember who they were. This could also be seen as more realistic, since people often give nicknames to others to remember a trait, characteristic, look, ect.
3) If you happen to go to a cyber cafe, just email the list to yourself and reintroduce it to your rented computer at your cyber cafe. Not to big of a deal; you\'ll live. :-P
Next, I like the idea of bubbles along with a chat menu. This way you can read the bubbles and if you miss anything just read the chat menu and pick up what you missed. I find this really realistic, as opposed to what the others have said about it. Sure, if there\'s lots of people, you won\'t be able to keep up with all the conversations, but it is my experience that in larger groups, people holding one conversation will form one group, another will form another group and so on. Also, I don\'t think names should be added to the chat menu. For the sake of reality, if you\'re in a big group of people you don\'t know, are you really just going to start blabbing for hours on end without introducing yourself at one point in the conversation? Besides, if this path is taken (the chat with \"person says\") it would force the player to introduce themselves to the people they are talking to in order to follow the conversations. In my opinion, this is as real as it gets. The only downfall would be to those who are anti-social: They\'ll get have to deal with a bunch of conversations that sound like they\'re coming from one person (who is of course, just known as \"a person\"). Also, if we\'re going for realism, the shout command should just be removed. How often do you hear a person yell across a city, only to have the urge to answer him with an equally loud yell? If we\'re basing this entire thread and idea off of reality, then everything these ideas are completely valid (as opposed to your beloved shout command).
To sum up this paragraph in one word: Adaptation. If the massive chat idea is to implimented, people will want to introduce themselves and learn who everyone is, if only to make the chat simpler. Also, if an introduction isn\'t made and conversation splits, the groups will separate to keep their chat understandable. All in all, players will adapt to the circumstances (much in real life) to gain a better, easier way of communicating with those around.
I hope my ideas can be improved upon, by myself and others.