Well, one thing it does not mean is the main title of RPJnr's post, that the surface temperature trend is overstated. There is nothing in the paper (despite three gratuitous plugs of Watt's photography site) that actually argues for the measured temperature trend being wrong in any way.Yet the conclusion of a temperature bias is the one prominently displayed as the headline of a blog posting, and echoed on several websites including Watts, which RP Jr is as yet not willing to amend or retract.
I am less than favorably impressed by this trend of writing papers of whatever quality, and then prominently but informally misrepresenting their results in ways to give substantively wrong comfort to one (or the other) side in a political debate. For a man who talks of separating science and politics, I am forced to conclude that RP Jr. sets a very peculiar example.
Note also that RP Sr is piling on at Watts, Pielke Sr. on warm bias in the surface temperature trend "Provides evidence of the significant error in the global surface temperature trend analyses of NCDC" and using Klotzbach as evidence toward the point. Now if that isn't telling the Watts crowd watt they want to hear, especially posted right after Roger Jr's thing, I guess I don't know watt is. Perhaps some judicious hairsplitting can save the latter headline, (like, for instance, "oh, I just meant the analysis is erroneous, not that the trend is actually wrong" and "significant means memorable or important, everybody knows that") but that is not straight talk by any means.
Whether Koltzbach and Pielke Sr. have actually resolved the temperature trend differential or not is something I am keeping an open mind about for now. But if they have, it means that both temperature records are substantially correct. I can't imagine why any scientist would be dissatisfied with a result like that, or what scientific motivation there could be to paint it as something else, and then trumpet the unsupported assertion as a new result on a contentious website like Watts'.