Questions about the accuracy of online traffic data are well known, though new numbers never fail generate a discussion. A batch of new charts have been making the rounds, and though you have to remain skeptical about the raw data, it does appear that the leaders in key categories are maintaining their grip.

-- ComScore’s latest look at the online video space has YouTube sitting comfortably atop the leaderboard, garnering 31 percent of all online videos viewed—up from 27 percent from the firm’s report in September. This is far ahead of its next closest rivals FIM (NYSE: NWS) and Yahoo (NSDQ: YHOO), which get 4.4 percent and 3.5 percent respectively. Interestingly, 51 percent of views come from outside the top ten sites. That’s actually a slight (possibly meaningless) decrease from comScore’s (NSDQ: SCOR) numbers in September, which had 54 percent of views coming outside of the top ten. Ultimately, even assuming the numbers are pretty much accurate, it’s still not clear what this means in terms of money. For all the hype surrounding online video, Google (NSDQ: GOOG), as of its latest 10Q, still is seeing a trivial impact from the business. Analytics firm Compete corroborates YouTube’s dominance.

-- E&P reports the latest Nielsen data on newspaper sites; NYTimes.com maintains its top billing, with 17.2 million unique audience members in December, up 30 percent from last year. USAToday.com and WashingtonPost.com rank second and third.  Long Island’s Newsday came in fourth, with a big 182 percent year-over-year gain, while WSJ.com—not the whole WSJ network—comes in fifth with 5.4 million unique users, up 109 percent. The growth of NYTimes.com isn’t hard to believe, as several reports have had its traffic growing since a redesign and the end of TimesSelect. The growth at WSJ.com also makes sense, in light of its creeping efforts to open up more of the site. The rest of the bunch is pretty scattershot, with various regional papers moving up or down, seemingly without a pattern. This is also just the data for one month, so it may not reflect broader trends.

-- The traffic trends in the social networking space shows how shaky internet traffic data is. The latest from HitWise has MySpace towering over Facebook, holding 72 percent of US market share compared to Facebook’s 16 percent. End of story? Probably not. TechCrunch has comScore’s latest for the two sites, showing a narrower gap in the US and a virtual tie on a global level. It’s not that that this information is any more believable, but it demonstrates how you can get a vastly different picture by slicing things differently or using a different method.

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