Email doesn't have an easy way to add someone to a thread, or to manage a forked conversation. It's closed and non-discoverable by default.
You add them to the cc list.
> or to manage a forked conversation.
Your email client is at fault there, any decent email manages forked conversations.
> It's closed and non-discoverable by default.
Thats why you have mailing lists which are indexed and searchable. You may see 'closed and non discoverable' as a downside, I do not. Anything that should be discoverable should be on a wiki.
I have very minimal experience using email, but doesn't this just add them to a new message as opposed to adding them to old messages?
Anyone reading the "to" line can see where the reader was introduced.
I'll be honest to say, most things that is said in any communication medium is a complete waste of time. Having i searchable rather than forcing it on people globally is the only scalable option.