jducoeur

I think you are making a classic computer geek mistake of mistating the problem. The problem isn't how one counts—starting with zero or one—the problem is "What kind of number should I use?" Conversation Number Zero may be placed in the database in the zeroth position, may be named "Conversation Number Zero" as I just have, or may use thread zero -- but it's still the FIRST conversation, and displaying the number ONE is the way to make that clear. For your own peace of mind, you may prefer to have it also use thread ONE and occupy database entry ONE, but that's YOUR problem, not your users', and should be invisible to them. To put it another way, the internal name can be anything you like, the DISPLAY NAME should be ONE.

"Conversation Number XXX" is, of course, ambiguous -- does that mean the Conversation NAMED XXX, or the XXXth conversation. I think that that ambiguity lies at the heart of the problem, and you want to stomp it out. Don't let implementation details sneak into your UI.