Fred Stutzman notes that Comscore has reported a dramatic change in the traffic seen at the Web sites of the two leading contenders for 2008 Democratic nomination:

• HillaryClinton.com’s audience of unique visitors dropped from 313,000 in January to 206,000 in February, a 34 percent drop.
• BarackObama.com’s audience of unique visitors grew from 297,000 in January to 376,000 in February, a 27 percent uptick.

Stutzman attibutes this to site design:

By embracing voter-generated content, Barack Obama has given supporters a reason to keep coming back to his site. The dropoff by HillaryClinton.com is telling – there was an initial groundswell of support, but without voter-generated content, what incentives do visitors have to keep coming back to the campaign property? No, they’re out on Youtube or Facebook supporting Clinton in their native places. Clearly, the voter-generated presence delivers stickiness, and a freshness of content that brings new visitors to the site.

While that’s interesting, it may not matter in terms of the truly important metrics for presidential candidates: Fundraising and votes.

While Obama’s site has now surged ahead of Clinton’s in visitors, the demographics are in Clinton’s favor. Stuzman notes that, “33 percent of Obama’s visitors are under 35, with 57.1 percent of Clinton’s visitors between 35 and 54. Accordingly, the visitors of Clinton’s site have higher incomes than that of Obama’s.” More importantly, though, 17 percent of Obama’s visitors are 18-24, compared with only 2 percent of Clinton’s. As the report points out,

“Historically, few political campaigns have focused on reaching out to 18-24 year olds because they are a notoriously unreliable voting bloc,” said Andrew Lipsman, senior analyst at comScore. “Indeed, our data show that 18-24 year olds are 20 percent less likely than average to visit political Web sites. Thus, it is particularly noteworthy that BarackObama.com is attracting such heavy interest among 18-24 year olds, because it speaks to Senator Obama’s ability to mobilize younger voters and offers an early indication that they may play a more significant role than usual in the 2008 elections.”

Now, Obama raised slightly more money than Clinton in the first reporting cycle. To the extent that’s attributable to his online effort, it’s important. Otherwise, though, it’s not yet apparent to me what website and Facebook buzz brings to someone running for president.