Email is the worst as you can't easily send to 3rd party conversation or attachments etc nor can non CC-ed person silently follow it. I use emails only to send

Email is the worst as you can't easily send to 3rd party conversation or attachments etc nor can non CC-ed person silently follow it. I use emails only to send people link to forums, docs, apps etc. and almost never to explain something - anything that needs explaining should be documented on central place so anybody can see it and follow it even 5 years from now. Forums should be the norm. They do not have all those IM/email problems. They are searchable, URLable, public or private, do not require client infrastructure and so on.