One definition: When I use “BBS,” I mean an on-line bulletin board system, typically with messages organized into topics and fora. Examples are implemented using phpBB, phpNuke, vBulletin, etc. You can make a good argument that Facebook and MySpace are fancier instances of BBSs and I think that's right.
When I use Facebook, I'm implying MySpace as well in most cases. I'll note the exceptions if there are any.
One to all
Apps: blog, Twitter
This is where one person wants to post messages to the world. A blog is the next to most recent way this is usually done and Twitter is the newest.
One to many
Apps: BBS, Facebook, subcription blog, Twitter with closed account
In this case, one person wants to communicate to a closed group of people. Everyone else is excluded from the conversations.
This is a mode I find myself using and it's where the BBS, Facebook and MySpace usually fit. In the email paradigm, the mail list filled this need.
It just occurred to me that a subscription blog, where the blog is limited to a set of registered users, may fit this instance much better. The discriminating factor concerns who does the posting. If everyone posts messages, usually, then the many to many model fits better. On the other hand, if I'm the one doing nearly all of the posting, then the subscription blog may be better. Subscribers can comment on the postings and they can even be given permission to post.
I and a small group of friends tried this in a brief experiment with Blogger but there was one feature lacking that made it unusable in my opinion. If someone went back and added a comment to an old posting, that new information wasn't indicated in any way. The old post didn't move itself to the top of the list or a notification wasn't sent. (Hm, there actually may have been a way to receive notifications of new comments). Just browsing the blog didn't make new comments obvious however.
There's a subtle continuum transition from the one-to-many to many-to-many.
Many to many
Apps: BBS, Facebook, Twitter with everyone using closed accounts
This is when you have a group of people that want to have closed communication, limited to the group. Everyone sends messages and those messages usually go to everyone else in the group or to a large subset.
This is where the BBS and Facebook, etc., are a big win, especially over the email model (which I claim is nearly obsolete). Single storage of messages, history of communication, limitation and control of who is in the group, and even in subgoups, makes such a system easily manageable and programmable.
I also think this spot is where there is the biggest potential for the biggest win.
Trying to manage this type of communication with email, especially at the corporate level, is now at disaster status. Any success at all is a result of huge effort and expense.
Using a closed BBS or Facebook (-like app) should represent a corresponding huge reduction in cost and effort with increased functionality and success.
All to one
Apps: web form, email
This is the answer to the question: How do I contact you? Most sites seem to have discovered the solution to this that I implemented years ago: the web form. You put up a web page with a form to fill out that allows anyone in the world a way to send you a message. But the content is controlled and it requires filling out the form as opposed to just sending email, which subjects the recipient to the spam problem. You can even use some of the mechanisms to verify that a human is filling out the form, like the so-called captcha schemes. (By the way, I really hate the name “captcha”).
One to one
Apps: email with white list, Facebook inbox, BBS private messages
This can be done with special features in each of the applications. Email with a white list handles this pretty well. The private message features in Facebook and BBS applications also do this.
Twitter allows one person to address another, as does the Facebook wall, but in a very public way. That's sort of a weird hybrid that's one to one with everyone listening. That type of public communication seems to be pretty popular, and seems to indicate some sort of declining interest in privacy.
If I did this right, I'd probably have seperate categories for one to one private and one to one public.
Facebook seems to be a solution to all of these except one to all and all to one. (Sounds like the Three Muskateers, doesn't it?) Sure, you can accomplish one to all if you open up your Facebook site so that it doesn't require adding you as a friend, but then you lose the one to many and many to many modes.
The all to one problem in Facebook is only solved by someone requesting that you add them as a friend, and that grants too much just so someone can send you a message, maybe only a one-time message.
What does this mean for me?
One, I may be putting a lot of effort into maintaining many to many solutions when, in fact, one to many is the problem I need to solve. I should consider moving to a subscription or hidden blog. A subscription requires a user account and permission to access the blog. The hidden case means the blog's URL is obscure and not listed or indexed. Anyone that knows the URL can access it, but they shouldn't be able to know it unless someone tells them.
This also includes a couple of email lists I've maintained over the years. Maybe I should move those to subscription blogs. I need to simplify things some how.
Two, I've already given in and started using Facebook. Email is more and more like the old hangout that is now empty. You walk in the door and there's no one there except some weasely sales guys here and there talking to each other and the email administrator behind the counter, wiping it with a cloth, with a sad look on his face. Or maybe he just looks tired. When you go looking, you find that everyone is down at Facebook.
Other conclusions and topics
It's time for email to die. I'm more and more convinced of this. I'll say more about this later, though most of the reasons are above.
The archival problem. Everyone is putting so much effort into Facebook and that record of their lives is now stored there. What happens as Facebook completes its arc and begins to fade. How do you personally archive all of your Facebook life? Do you even care? Maybe not. I think Twitter has an even shorter arc and of course no one is sure what will come next. As each of these (probably shorter and shorter) arcs occur, some of us will worry about how to archive each one. Some will worry too late and some won't care. It would be nice if there was some homogeneous medium to put it all in and make it searchable. Please find something better than XML before we go to far down that road!