> Hello.

> I'm looking at the idea of automatically establishing two-way links
> between resources--in particular, sioc:reply_of and sioc:has_reply
> between two posts, one of which is a reply to the other. If such a
> mechanism were in place, various communities could automatically link
> together to form a sort of a distributed discussion space, and threads
> could be followed from one site to another.

> Do you think this is a good/useful idea?
> Are there any implementations of it that I'm missing?

> Now there are several ways of accomplishing this already deployed on the
> Web, such as trackbacks[1] and pingbacks[2]. I'm considering if they
> could be used "as is" for the purpose. However, in my view they have an
> important drawback: they only assert that there is *some* kind of
> relation or link between two resources; (e.g. WordPress, as it seems,
> automatically pings back every resource that's linked to from a post).
> Thus if we were to use trackbacks or pingbacks for establishing
> *semantic* links, the receiving end of the trackback would need to
> compare the entire description of a resource to its own previous
> conceptions of it (to infer what has been created or changed). If the
> relationship would be identified in the protocol itself, life would be
> easier.

> Do you think trackbacks/pingbacks would suffice for the purpose I
> described?

> FWIW, I've written some code to illustrate a possible trackback-like
> protocol for making arbitrary semantic links between resources. Say we
> have a post Y that is a reply to post X. The protocol consists of three
> steps:

> 1. Y's server requests an (RDF) description of X and searches for a
> certain statement of the form "X has_siocback Z". Z is the trackback
> ("siocback") resource for X (could be X itself).
> 2. Y sends a POST request to Z with three parameters--subject, predicate
> and object--which together form a triple identifying the new
> relationship. In our case, "Y sioc:reply_of X".
> 3. Z applies adds the statement "X sioc:has_reply Y" to its description
> of X. Now clients obtaining the "authoritative" description of X will
> see that has a reply Y.

> My example[3] implements this in a context of a trivial blog-like site.
> It needs Python 2, CherryPy 3 and RDFLib. Interested people could fire
> up a few copies and see how they establish the links.

> Feedback welcome.

> [1] http://www.sixapart.com/pronet/docs/trackback_spec
> [2] http://hixie.ch/specs/pingback/pingback-1.0
> [3] http://sioc-dev.googlegroups.com/web/siocback.py

> --
> Vasiliy Faronov