• by Mark Walsh  @markfwal, October 20, 2008

A tight presidential election and a deepening financial crisis were the two key factors driving Internet traffic in September, according to new comScore data for the month.

As investors obsessively tracked their portfolios amid the global financial meltdown, traffic to business and finance sites increased 9%, with top financial sites making even bigger gains.

Foxbusiness.com more than doubled traffic in September to 1.2 million unique visitors, Google Finance jumped 67% to 1.4 million, and category leader Yahoo Finance climbed 30% to 20 million. CNBC.com rose 20% to 1.6 million.

Not only were more people visiting these sites, but they were looking at more articles and spending more time on average than before, according to comScore.

"The ability to track the market on a minute-by-minute basis and access banking and trading accounts quickly enables Americans to make financial decisions in real-time," said Jack Flanagan, executive vice president of comScore Media Metrix, in a statement. "Whether these decisions are sound or not is another story."

Traffic to online trading sites grew 10% to 12.6 million, with sites such as E-Trade.com, TD Ameritrade.com and Schwab.com up more than 25%.

The spike in traffic to financial sites seems like a strange twist, given that ad spending by the financial services industry fell 27% during the first half of the year, according to Nielsen Online. But spending by financial sector advertisers on finance-related sites actually increased 8% during that period, Nielsen found.

On the political front, the Web sites of both Barack Obama and John McCain enjoyed big gains as the presidential race entered the home stretch. Obama's campaign site jumped 37% to 5.4 million, while his Republican rival's Web audience more than doubled to 3 million.

Politics was the top-gaining category for the second consecutive month, experiencing a 43% increase to more than 20 million visitors, as interest in the Republican National Convention in early September and the first presidential debate later in the month generated heightened interest.

Both BarackObama.com and the politically focused HuffingtonPost.com were among the top ten fastest-gaining sites (among the top 250 Web properties), with the HuffPo increasing 38%.

No data yet on traffic surging to JoethePlumber.com.