Dan Connolly's tinkering lab notebook

Consensus and community review in open source and open standards

Consensus is a core value of W3C and lots of other open standards and open source communities. I used to think that a decision where almost everybody agreed except a few objectors was an example of consensus. That was based on my experience in the IETF, with its "rough consensus and running code" mantra. Then I learned that this is quite a stretch with respect to the normal dictionary meaning of "consensus".

The debian community seems to be examining the meaning of "consensus":

Many things are done on behalf of the project without every individual member supporting them - for instance, Mark is vigorously opposed to Debian UK being granted a trademark license, even though Branden (and therefore the project) granted one. The key difference here is the difference between consensus and unanimity.

Matthew Garrett 2006-04-04

Definitions of "consensus" vary. The wikipedia article on consensus has a good synthesis: Achieving consensus requires serious treatment of every group member's considered opinion.

W3C's consensus policy formally distinguishes the case of even one objection from consensus:

The following terms are used in this document to describe the level of support for a decision among a set of eligible individuals:

  1. Consensus: A substantial number of individuals in the set support the decision and nobody in the set registers a Formal Objection. Individuals in the set may abstain. Abstention is either an explicit expression of no opinion or silence by an individual in the set. Unanimity is the particular case of consensus where all individuals in the set support the decision (i.e., no individual in the set abstains).
  2. Dissent: At least one individual in the set registers a Formal Objection.


In some cases, even after careful consideration of all points of view, a group might find itself unable to reach consensus. The Chair may record a decision where there is dissent (i.e., there is at least one Formal Objection) so that the group may make progress (for example, to produce a deliverable in a timely manner). Dissenters cannot stop a group's work simply by saying that they cannot live with a decision. When the Chair believes that the Group has duly considered the legitimate concerns of dissenters as far as is possible and reasonable, the group should move on.

That last bit is important, since "you can't schedule consensus," another lesson I learned from Michael Sperberg-McQueen. And we do try to schedule our deliverables.

The RDF Data Access Working Group (DAWG) has been working on SPARQL for quite a while now. Our first public release was October 2004. Since then, we have handled comments from a few dozen people and tried to reach consensus with them. We weren't always successful. Our request for Candidate Recommendation shows the outstanding formal objections, each one of which got reviewed by The Director. Though W3C did grant that request for Candidate Recommendation status for SPARQL today (yay!), we need to go back over some of the comments and make test cases and maybe some clarifications. I hope that, in the process, we can address some of the concerns of those with formal objections and achieve consensus with them.

Also, I remember a time though I can't confirm from The Tao of IETF or any of the other records that I searched when people and companies who wanted to deploy new technology on the Internet were expected to submit their proposal for community review before deploying widely. I wrote a message on squatting on link relationship names, x-tokens, registries, and URI-based extensibility to www-tag in April 2005, with concerns about several mechanisms which were deployed, some at giga-scale, as far I can tell, without any community review. I think I'll repeat just about the whole thing:

When somebody wants to deploy a new idiom or a new term in the Web, they're more than welcome to make up a URI for it...

"[URI] is an agreement about how the Internet community allocates names and associates them with the resources they identify."


We particularly encourage this for XML vocabularies...

The purpose of an XML namespace (defined in [XMLNS]) is to allow the deployment of XML vocabularies (in which element and attribute names are defined) in a global environment and to reduce the risk of name collisions in a given document when vocabularies are combined."


But while making up a URI is pretty straightforward, it's more trouble than not bothering at all. And people usually don't do any more work than they have to.

There is a time and a place for just using short strings, but since short strings are scarce resources shared by the global community, fair and open processes should be used to manage them. Witness TCP/IP ports, HTML element names, Unicode characters, and domain names and trademarks -- different processes, with different escalation and enforcement mechanisms, but all accepted as fair by the global community, more or less, I think.

The IETF has a tradition of reserving tokens starting with "x-" for experimental use, with the expectation that they'll shed the x- prefix as they're registered by IANA. But it's not really clear how that transition happens.

Witness application/x-www-form-urlencoded. A horrible name, perhaps, but nobody has enough motivation to change it. It's been all the way thru the W3C process... twice now: once for HTML 4 and again in XForms. Hmm... I wonder if it's registered... nope.

A pattern that I'd like to see more of is

  1. start with a URI for a new term
  2. if it picks up steam, introduce a synonym that is a short string thru a fair/open process

I'm not sure where the motivation to complete step 2 will come from, but if it doesn't come at all, that's OK. Stopping with a URI term is a lot better than getting stuck with something like x-www-form-urlencoded.

Lately I'm seeing quite the opposite. The HTML specification includes a hook for grounding link relationships in URI space, but people aren't using it:

when Google sees the attribute (rel="nofollow") on hyperlinks, those links won't get any credit when we rank websites in our search results.

google Jan 2005 announcement

By adding rel="tag" to a hyperlink, a page indicates that the destination of that hyperlink is an author-designated "tag" (or keyword/subject) of the current page."

technorati RelTag

What are the prefetching hints?

The browser looks for either an HTML <link> tag or an HTTP Link: header with a relation type of either next or prefetch.

mozilla prefetching FAQ

Google is sufficiently influential that they form a critical mass for deploying these things all by themselves. While Google enjoys a good reputation these days, and the community isn't complaining much, I don't think what they're doing is fair. Other companies with similarly influential positions used to play this game with HTML element names, and I think the community is decided that it's not fair or even much fun.

Deployment of the technorati RelTag thingy seems much more grass-roots, peer-to-peer. But even so, it's only a matter of time before we see a name clash. So perhaps it's fair, but it doesn't seem wise.

I think all three of these are cases of squatting on the community resource of link relationship names.

Should all new link relationships go thru the W3C HTML Working Group? No, of course not. The profile mechanism is there to decentralize the process.

Should W3C run a registry of link relationship names? That seems boring and inefficient, to me. It can't possibly cost less time and effort to apply for a W3C-registered link relationship name than it can to reserve a domain name and run a web server, can it?

If Google and Mozilla really want the community agree to these short names, I'd be happy to see them use the W3C member submissions process.