Willie Sutton would be proud. In Willie’s day the money was in bank vaults, and that’s why he robbed them. Today, the money is online.

According to the new eMarketer report, Financial Services Online Marketing, the US financial services industy’s online ad spending will increase by 33.3% this year and it will reach $3.52 billion in 2010.

"Last year, financial services accounted for 12% of all online advertising, about $1.5 billion of the total $12.5 billion spent online last year," says Lisa Phillips, eMarketer Senior Analyst and author of the report. "In fact, the category’s total in 2005 represented a decline of 8.1% from 2004 spending levels, when financial services accounted for 17% of all online spending."

This year, however, got off to a fast start, with a huge increase (139%) in the number of financial service display ads served between December 2005 and April 2006, according to report from Nielsen//NetRatings.

The pace will probably remain torrid through the summer, and slacken in the final quarter of the year around the holidays and the Congressional mid-term elections.

"Search advertising, an area not tracked by some researchers, is a major expense in some financial segments, such as mortgages, loans and investments, and a necessary one in all others," says Ms. Phillips. "Cost for pertinent keywords could go higher across the board as more and more debt-strapped US consumers turn to the Internet for help."

In addition, the rich media format, currently the least-used by financial marketers, could gain favor as a way to introduce new products, benefits and financial tools to consumers.

"Financial service marketers are testing more interactive channels to reach consumers," says Ms. Phillips.

Behavioral targeting is one of them: 72% of financial services marketers polled by Forrester Research late in 2005 said they were either using, piloting or planning to try the tactic in 2006. Rich media display ads and contextual targeting were also high on the list.

Emerging tactics, such as blogs, social networks, mobile marketing, podcasts and RSS and advergaming, were less popular, but on the radar of about one-third to one-quarter of the financial services marketers surveyed.

More here.