Back in March of '09, I posted Get ready for fourth party services here, calling them "a classification for user-driven services" and "a place where a vast new marketplace can open up, serving customers first". (Or users, if they're not paying, which is the case for most of what we get free (as in beer) on the Web.)

Later I unpacked it a bit, in VRM and the Four Party System, over at ProjectVRM, where I've been encouraging user-serving development and research over the last few years. While the VRM development community has been using "fourth party" quite a bit (see Phil Windley's postings here and here), we haven't seen the term much outside the community.

That is, until yesterday, when I ran across this tweet by @Jonathan Mayer, courtesy of a re-tweet by the Wall Street Journal's @WhatTheyKnow folks:

We've open sourced FourthParty, the web measurement platform in our Tracking the Trackers studies. http://t.co/52xqSn9

Explains the About page,

FourthParty is an open-source platform for measuring dynamic web content. Unlike many previous web measurement tools FourthParty is built on a production web browser, Mozilla Firefox, lending it the ability to:

• monitor realistic interactions with web applications, crowdsource data from actual users,
• take advantage of existing browser extensions and automation tools, and
• run on just about every modern desktop operating system.

FourthParty is fast, modular, and already generating research results. Get started measuring the web!

So there's your cue. I'll be interested to hear who lines up to help and what they find (or help find).