I'm trying to find a similar solution for non-profit and NGO organizations and small friend groups.
Something which combines
a) one-to-group of Facebook or Google+,
b) document creation of TiddlyWiki and
c) simultaneous editing of EtherpadLite
I've found Kune to be among the better implemented candidates as one of it's main design goals is ease-of-use for small groups, communities and non-profits.
Zero system administration as hosting is free.
Ease of customization via Wave Gadgets.
While still in alpha stage it looks good.