One of the “Web 2.0″ features people always want in a repository interface is the ability to annotate or comment upon the record. Unfortunately, the commenting environment in many systems is very basic and make it difficult to create the kinds of annotations that could be truly useful.

To help overcome the environmental challenges and constraints, what if you could make comments in your personal content management system (like, say, a blog) and have that recorded within the repository?

There’s an obvious mechanism here, already employed by many blogging systems: Trackback

A trackback is one of three types of linkbacks, methods for Web authors to request notification when somebody links to one of their documents. This enables authors to keep track of who is linking, and so referring, to their articles [http://en.wikipedia.org/wiki/Trackback].

In a repository that already employs linked data, adding a trackback is fairly easy and an obvious way of providing (tech savvy) users the ability to comment and curate collections, while creating a reference in the repository itself. Implementing trackbacks is as simple as adding this in the header:

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/">
<rdf:Description
rdf:about="http://path/to/this page/pid/wgbh%3A131#this"
dc:identifier="http://path/to/this page/pid/wgbh%3A131#this"
dc:title="Interview with Robert McFarlane, 1996 (Part 1)"
trackback:ping="http://path/to/action/trackback/pid/wgbh:131">
</rdf:Description>
</rdf:RDF>