He learned of this userscript by reading a recent paper in ACS Chemical Biology by D.P. Martinsen, "Scholarly Communication 2.0: Evolution or Design?". This was news to me, so I checked it up. It turns out that it's pretty much a review of the Spring ACS sessions on Web 2.0. He begins by giving a good description of what the term Web 2.0 means, and why scientists should know about it. Then he goes on to discuss the presentations by Nick Day, Henzy Rzepa and Colin Batchelor among others (these are just the people I know or know of).
Then we come to the good bit. At the end of page 370 it says:
Two additional items, unrelated to the ACS meeting, are significant. Using Greasemonkey, a Firefox extension that allows anyone to write scripts that can change the way a web page looks, the Blue Obelisk group, a community of chemists who develop open source applications and databases in chemistry [ref to BO paper], has created several such scripts to enable chemistry-related features. One of these tools will insert links to blog stories about journal articles into the tables of contents of any ACS, RSC, Wiley, or NPG journal [ref to old BO wiki]. This enhancement to a journal’s table of contents is completely independent of the journal publisher.That's a pretty lucid summing up of the userscript and its significance. Somewhere I suspect PMR's hand in this. :-)