I think the idea of superimposing fact-check results on pages that contain checked phrases is pretty cool. It would certainly be more welcome than the "mouse-over ads" that some sites currently employ!<p>Spoofing could be a problem. Right now there are misspelled domains registered, pages that look almost identical to real pages from banks, and plenty of other scams. Something would have to ensure that the authentic browser add-ons and fact-check results would be very difficult to fabricate (otherwise a disreputable site could simply make itself look reputable).