Going back probably all the way to 2003 (I can’t easily pinpoint, as obvious mail searches turn up lots of hand-wringing about structured data in/for web pages, something which persists to this day) people have suggested using something like trackback to notify that someone has [re]used a work, as encouraged under one of the Creative Commons licenses. Such notification could be helpful, as people often would like to know someone is using their work, and might provide much better coverage than finding out by happenstance or out-of-band (e.g., email) notification and not cost as much as crawling a large portion of the web and performing various medium-specific fuzzy matching algorithms on the web’s contents.

In 2006 (maybe 2005) Victor Stone implemented a re-use notification (and a bit more) protocol he called the Sample Pool API. Several audio remix sites (including ccMixter, for which Victor developed the API; side note: read his ccMixter memoir!), but it didn’t go beyond that, probably in part because it was tailored to a particular genre of sites, and another part because it wasn’t clear how to do correctly, generally, get adoption, sort out dependencies (see hand-wringing above), and resource/prioritize.

I’ve had in mind to blog about re-use notification for years (maybe I already have, and forgot), but right now I’m spurred to by skimming Henry Story and Andrei Sambra’s Friending on the Social Web, which is largely about semantic notifications. Like them, I need to understand what the OStatus stack has to say about this. And I need to read their paper closely.

Ignorance thusly stated, I want to proclaim the value of refback. When one follows a link, one’s user agent (browser) often will send with the request for the linked page (or other resource) the referrer (the page with the link one just followed). In some cases, a list of pages linking to one’s resources that might be re-used can be rather valuable if one wants to bother manually looking at referrers for evidence of re-use. For example, Flickr provides a daily report on referrers to one’s photo pages. I look at this report for my account occasionally and have manually populated a set of my re-used photos largely by this method. This is why I recently noted that the (super exciting) MediaGoblin project needs excellent reporting.

Some re-use discovery via refback could be automated. My server (and not just my server, contrary to Friending on the Social Web; could be outsourced via javascript a la Google Analytics and Piwik) could crawl the referrer and look for structured data indicating re-use at the referrer (e.g., my page or a resource on it is subject or object of relevant assertions, e.g., dc:source) and automatically track re-uses discovered thusly.

A pingback would tell my server (or service I have delegated to) affirmatively about some re-use. This would be valuable, but requires more from the referring site than merely publishing some structured data. Hopefully re-use pingback could build upon the structured data that would be utilized by re-use refback and web agents generally.

After doing more reading, I think my plan to to file the appropriate feature requests for MediaGoblin, which seems the ideal software to finally progress these ideas. A solution also has obvious utility for oft-mooted [open] data/education/science scenarios.