I have sampled all of it. I mean ALL of it.
Most mediums have an interesting or functional thing about them (except twitter which has no function whatsoever). Most have really big bad points.
Life is about incongruent schedules and communicating.
Any medium that can queue information is immediately usable and has function.
I was going to go on with the science of it, but I'll just cut to the chase and offer that a forum done right (not this one) beats them all.
Messages can be queued, multimedia embedded or linked to easily, there is a 1 to many relationship or a 1:1, your choice. It is organized by topic. The information is indexed and searchable.
What is missing from a modern Internet forum (other than ezbored)?
Internet forums are the production side of the Internet. This is where the horsepower is. Every time. I mean EVERY time I go searching for something it is either on wikiepdia of on a forum. EVERY time. It is where ALL the info is. The rest of the Internet is noise, porn, and places to buy shit.