I have taken to using Facebook as a place where I put a second copy
of something I’ve already written and published somewhere else.
That ensures that in some way I’ll be able to find it, probably by
googling my blog posts. Things written on Facebook disappear into
the ether too quickly (including this thread which will die quietly
when we are all done with it).
Facebook Communities suffer from the problem that they don’t really
provide an equal forum for all people to share jointly in a topic
discussion. Rather, they bias towards the moderator’s interests,
because only the posts from the moderator are visible for long
enough to get any traffic.
The problem of how to build forum software is old and solved. The
MTS Confer system and others that followed it like Picospan and Caucus
lived in a world where you could create a long-running discussion
that focused on one topic and where you could keep that topic mostly
on-topic over an extended period of time. Facebook, in contrast,
feels more like a big chat room, where yesterday’s posts scroll off
into nothingness and where you can’t get back to any discussion you
once had – no matter how good it was.
Twitter doesn’t give you the paragraph-sized chunks of discussion that
you need to actually have an intelligent conversation, but it does
have long-lived hashtags that enable a community of interest to form
and (with scheduled chats) thrive. It’s possible to find people who
you don’t know who share an interest and to communicate with them in
such a way that a simple enough search brings back something useful.
Nothing on Facebook behaves that way.
Further reading –
See this thread on Facebook which prompted this post, started by
Jim Benson and contributed to by Howard Rheingold and others.
Edward Vielmetti's Wordpress weblog 
For individuals, in theory FB’s “Notes” can sort of approximate this behavior (e.g. a note I wrote a while back: https://www.facebook.com/notes/marc-vanheyningen/on-the-passing-of-christopher-hitchens/10150560827288804 ) They stick around and can relatively easily be referenced later.
In practice, however, they’re not used that way (at least in my experience.) They’re used just like other status posts: people see it and maybe comment on it when it first shows up, then quickly forget about it. The only time you see a lengthy conversation is when two or more people have strong opinions and a desire to get in the last word, and it’s seldom worth reading later (or even at the time.)
I kinda have to assume this is, at least in significant part, due to the notion that this is what people want. FB, unlike something like Confer or PicoSpan, is mostly person-oriented (rather than topic-oriented) and so people go there wanting to find “What are my friends up to?” rather than “Where can I find a discussion about topic X?”
Ideally, conversation flow just happens, but what do you do when you’re stuck? For such situations, it is important to be aware of the ingredients that make a natural conversation flow and consciously use them when required. Great article.