If you are currently using Rhino to run Javascript then PhantomJS makes for an excellent and more functional replacement.
In addition to running library unit tests in a 'real' browser environment it can also be used to test apis and visual components, and then save results as files and screenshots for use with other systems such as Hudson.
I use it extensively for our web app build and test cycle at work (Causata.com) and to save time for anyone interested in rolling their own have made the code available on Github at https://github.com/metafeather/phantomjs-yuitest
You'll probably find that most of the requests you saw in Firebug are for the Inspector tool (built using YUI2).
The jshub.js file is the only 'tag' needed on a website (+ jquery if not already in use) and is designed to provide a 'hub' API for each vendors plug-in to query the data collected and send it on its way to a receiving server so only one file need be maintained as vendors come and go.
One of the key reasons for using a microformat (hPage) is the principle to "design for humans first and machines second".
We provide an Inspector tool on our Demo store to meet this principle and hope that, with the microformat's community's help, we can make the data visible in many other tools.
We would like to make website publishers and users more aware of the data being declared and collected so it can be more accurate and therefore more beneficial to all involved.
Currently many users are unaware data is being collected at all.
This is a noble goal — letting the user and site publisher know what data is collected — however, I don't see what the benefit is to the ad providers or data collectors on the sites, other than that they might possibly be able to simplify their Javascript and reduce the load time in pages with that use their scripts.
Am I missing something? Unless consumers start demanding to know what information is collected about them, I don't think that the benefits jsHub has for ad providers are important, and that they won't implement a plugin until they're pushed by some other forces. In other words: the merit of technical innovation isn't enough for them to change their behavior, and they need a bigger incentive in order to consider using jsHub at all.
