The Pew Internet and American Life Project has just published the results of a study on American’s e-commerce habits. Among the findings: 58% of Americans say they perform online research on the products and services they’re considering buying. That’s up from 49% who performed online research in 2004.

If you look at that number in terms of Americans who say they’re Internet users, that figure rises to 78% who research online before buying.

And it isn’t simply the number of Americans doing online research that’s grown. It’s the frequency with which we’re doing it. On any given day, 21% of adults are conducting this sort of research, up from 9% in 2004.

Americans Researching, Reviewing, and Buying More Online

In addition to reading about products and services online, more people are contributing reviews and sharing their opinions about products and services, particularly via social networks. 24% of American adults say they’ve posted comments about a purchase they’ve made.

The Pew study also looked at Americans’ e-commerce spending habits, in addition to their research habits. It found, not surprisingly, that the percentage of Americans purchasing products online rose from 36% in May 2000 to 52% in this 2010 survey. And the percentage making travel reservations for airline tickets or hotel rooms rose from 22% to 52% over the same time period.

The study found little difference between men and women’s online research habits, but did find that those in higher income brackets do more online research than those in lower income brackets. Those in higher income brackets and with more education also post reviews and comments more frequently.

“Many Americans begin their purchasing experience by doing online research to compare prices, quality, and the reviews of other shoppers,” says Jim Jansen, Senior Fellow at the Pew Research Center’s Internet & American Life Project. “Even if they end up making their purchase in a store, they start their fact-finding and decision-making on the internet.”