A small addition at Google Scholar. They’re now pulling out a right-hand identifier for the few free PDFs that appear in search results, to distinguish them from paywall PDFs…

Although it does fall down on muse.jhu.edu — which is effectively a paywall site, albeit a worthy one. And I did see one such link for emeraldinsight.com (although most emerald links didn’t have it), so the feature obviously still needs a little more tweaking.

Of course, if you use JURN then you can assume that everything in the results is free.