Direct messaging in a social web architecture

March 31, 2010 | 3 comments

This post is the third segment in my series on an architecture for the social web. Previously: How social networks can replace email, which is a non-technical approach to the issues, and my follow-up describing how to build a social web architecture using available technology today.

So what about direct messaging?

In my previous post, I described content notifications in the social web as being Activity Streams updates in response to requests signed with an OAuth key. Each individual contact would have his or her own OAuth key, and the system would adjust delivered content depending on access permissions I had assigned to them.

A private message in this architecture could just be represented as an item of content restricted to a small set of recipients (in the email use case, this is typically just one), with replies delivered using Salmon. The advantage of this approach is that the message doesn’t have to be text; it can be audio, video, a link to live software, or something else entirely.

However, while this is technically feasible, it may not always be desirable. We know from Google Wave, which also pushes the boundaries of person-to-person messaging, that an open definition of what a message contains can get very messy very quickly. Although I was one of the first people to have one, I no longer check my Wave account regularly. I believe this is mostly a user interface issue: Wave is an awesome collaborative document editor (what I’ve heard described as “a massively multiplayer whiteboard”), but not in any way the evolution of email that its development team claimed.

Therefore, I think it’s useful to think about the difference between a document and a message:

  • A message is the body of a communication.
  • A document is a bounded representation of some kind of information.

While in many ways they’re the same, I think it makes sense to make a separation on the UI level. As we’re discussing a decentralized architecture here, some kind of semantic marker in our activity stream feed to mark something as a message would be a useful feature.

Messaging “out of the blue”

You know where you are with an email address. Mine is Anyone who encounters that string of characters, whether on a website like this one, a business card or a scribbled note on a piece of paper, is able to send me a message from anywhere in the world. In the 17 years I’ve had an email address, the list of friendships and business connections I’ve made, and opportunities I’ve received and developed, through this simple mechanism has been uncountable. It’s also likely to continue far into the future.

Compared to this, visiting someone’s social web profile and sending them a message from their web presence is a hassle. Compare these steps:

  1. Receive the address of someone’s profile
  2. Click the “follow” button either on the profile itself or on the toolbar of your social web compatible browser
  3. Wait for the contact to follow you back
  4. Send your message


  1. Receive someone’s email address
  2. Send a message to that address

It’s simple, ubiquitous, decentralized and universally compatible. In fact, it seems hard to improve on, doesn’t it?

However, as this is a thought experiment about how social networking can replace email, let’s see if we can simplify this process somewhat. In my previous post, I discussed how a connection could be established with OpenID and OAuth through a web-based interface on a social web profile. How can we make this as simple as emailing someone, and cut out most of the steps I’ve listed above?

Connecting programmatically

I propose two additions to my previously discussed mechanism. The first is to expand the connection protocol to include a message. If someone connects to me on LinkedIn or Facebook, I receive some explanatory text from them, so it makes sense to include this feature in our decentralized social web architecture. It is likely that this would be an added parameter to the OAuth request token procedure.

The second is to allow connections to be made programmatically through a custom application. Just as we use email clients now, a social web client could automatically send a connection request. In keeping with our principle of using existing technology where possible, this is a simple OAuth connection request from the application, which includes a user message as described above. The application knows our details because we’ve set our preferences, so we’re never visibly redirected to a web browser to complete authentication. (In fact, this could take place using xAuth, a version of the OAuth protocol being developed for just these sorts of browser-free use cases.)

Whether we can send a follow-up message now depends on the receiving party. We have our OAuth token, and while it remains valid, the receiving social web node may choose to ignore any follow-up requests.

Our procedure has become:

  1. Obtain address of someone’s social web node (you could even infer it using WebFinger)
  2. Send a message to that node, bundled with a connection request

This is significantly better, and is comparable to the simplicity of email.

You may be wondering about the wisdom of adding everyone you contact as a connection. In fact, there’s some precedent for this already in applications like GMail. It’s important to note that not every connection need be a friend: in some ways, you can think of your total list of connections as your contact book. Some are important, some can be safely squirreled away until you need to contact them again. In this context (or any context where people you have a relationship with and people you’ve contacted are merged into one set), an adequate person management interface – or CRM to you and me – becomes important.

Next, and finally: let’s make our distributed social web architecture reliable enough to use in enterprise environments, using message queue protocols like ZeroMQ and AMQP.

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  1. Are you envisaging that these direct messages would replace email? Because I really wouldn’t want to have any kind of long-term connection with a fair number of the people I have exchanged email with.

    Andrew Ducker March 31, 2010 (3:55 pm)
  2. No, I wouldn’t either. This is similar to the Gartner prediction though – for example, if Facebook were to replace email, you’d also probably have an enduring connection of some kind.

    The solution may be to place some kind of time limit on these connection requests. After a while, unless the connection is persisted through further communication or a content subscription, it simply fades away.

    I do think it’s important to draw a line between these connections and, say, a friend connection on LinkedIn or Facebook. Think of it this way: a friend connection is a generic social web connection, but not all social web connections are friend connections. They’re kind of back-end infrastructure pipes.

    Ben Werdmuller March 31, 2010 (4:02 pm)
  3. It’s more that I’ve emailed, say, Cisco customer support. Or my hosting provider. Or some person who’s blog I liked. I send emails to people who I never expect to have any contact with again. Maybe I’m just odd :->

    Andrew Ducker March 31, 2010 (5:23 pm)

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