One mitigating factor (though not as mitigating as I'd like) is that PR fluff, at least of the direct-editing variety (versus placing positive media articles th

One mitigating factor (though not as mitigating as I'd like) is that PR fluff, at least of the direct-editing variety (versus placing positive media articles that then get cited in Wikipedia) tends to be most successful on the articles people read least. If a country hires a PR firm to insert propaganda into an article on an ongoing international conflict, it's much more likely to get removed or modified, vs. if an obscure company hires a PR firm to fluff its Wikipedia article. Likewise a major company like Microsoft or Google will have a harder time fluffing its article than the obscure company would, because more people are watching and editing the Microsoft/Google pages. One area where it comes up a lot is that a bunch of academics' articles are total fluff written by the university communications department, but also, nobody reads or cares about those articles. There are admittedly areas where that isn't true, articles with many readers but relatively little editor interest. Some tourist destinations are like that: lots of people may google for them, but there often isn't very much to write about them in good, cited sources. So they get relatively little legitimate editing, and lots of travel spam. I personally make it a point to systematically go through the pages on Greek islands and island villages once a year or so to clear out the hotel/car-rental/etc. spam.