lucy24 - 3:03 am on May 24, 2011 (gmt 0)
Webmasters who think that having a blank preview in the SERPs will affect the click-through rate and harm their bottom line certainly wouldn't do it.
It isn't blank. You get a preview-shaped white box that says "No preview available". So the question is how your ordinary human would react to this: "Well, screw 'em, I can't be bothered" vs. "Oh well, I'll just go ahead and click then."
I'm kinda inclined to think that the hypothetical ordinary human would assume that google just hadn't got around to making the preview-- or that they couldn't do it for some arcane, boring technical reason-- or that there was some random inexplicable rule governing which sites got preview. Not that the site itself had said Nuh-uh, keep your nasty previewbot offa my land.