Despite a huge increase in ad spending on the Internet last year – some 263%, according to the U.S. Internet Advertising Bureau – there’s a dearth of advertising directed to women and other groups, says an expert in on-line advertising.

Robbin Zeff, president of Arlington, Va.-based The Zeff Group, was speaking last month at the Internet World Canada conference, where she outlined her Top 10 Trends in On-line Advertising.

Zeff says marketers should keep in mind that women make 85% of the consumer product choices in a household, and that a lot of those decisions involve on-line research.

She also says that more than half of the women who are currently using the Internet are shopping on-line, making them open to advertising suggestion.

‘We used to joke that the Web was all about men with money and modems – it’s not about that anymore,’ said Zeff in an interview following her presentation.

Zeff also talked about the emergence of targeted e-mail advertising, the creation of better banner advertising, and further increases in ad spending – as more and more ad agencies buy into the medium.