The study found the growth in the number of customers at the 10 most-visited online banks hardened in 2008 as financial institutions became more aggressive in their customer acquisition efforts, after weak gains the previous year.

Over 51 million Americans visited one of the top ten online banking sites in the fourth quarter of 2008, around four million more than in the same period the previous year.

ComScore says nearly 60% of the total US Internet population now visits any one of the top 20 financial institutions' sites in any give quarter.

The study also examined customer satisfaction with online services and a survey of over 4800 US adults shows 71% are "highly satisfied" with their primary online bank - just one per cent down on the previous year.

Satisfaction with credit card issuers also held steady at 62%, compared to 65% the previous year.

However, brokerage firms saw their highly satisfied customers decline from 70% of respondents in 2008 to 58% in 2009.

"Given the performance of the financial markets in the past year, it's not surprising that brokerage customers with declining balances would not be as satisfied as last year," says Marc Trudeau, senior director, comScore. "It's interesting that a negative halo effect was not seen with respect to banks and credit card issuers, perhaps because of the reliability of services and the outreach they provided during a time of financial strain for many customers."

Respondents were also quizzed on their interests in online tools to help manage their finances. More than 60% expressed interest in free identity theft services, while free credit score monitoring appealed to 52%.

Around 37% showed a strong interest in online personal financial management tools, with half of those interested indicating they were willing to pay a modest monthly fee for the services.

An instant messaging service would appeal to 30%, widgets to 27% and blogs to 20%.

Says Trudeau: "It's clear that most customers are paying close attention to their personal finances, and, consequently, for the banks that step up and provide customers with the tools they're requesting, it's an opportunity to both cultivate and solidify customer relationships and to potentially drive incremental revenue as well."

The results contrast with another recent comScore study, which suggested that engagement at many of the top banking sites declined in Q3 2008 versus a year ago. Four out of the top five online banking sites experienced declines in the average number of minutes spent per visitor in the third quarter of 2008 versus a year ago.