Online shoppers spend more time researching products before buying them, according to a joint survey by Krillion, a Mountain View, Calif.-based online shopping site, and the e-tailing group, a Chicago-based consulting firm.

In a poll of 1,000 consumers who spend more than $500 a year online, 67 percent said they typically devote 30 percent or more of their online shopping time researching products, while 42 percent said research takes up more than half of their time.

Not surprisingly, manufacturers' Web sites were the most common resource for online product research, followed by retailers, the survey found. About half of the respondents said they turned to comparison shopping sites to gauge prices. As many as 65 percent said blogs were the least important resource.

Of all product categories, consumers said they spent the most time researching new computers -- taking several weeks and even months before deciding on a purchase.

"Manufacturer Web sites are clearly critical links in the information gathering process," Lauren Freedman, president of the e-tailing group, said in a statement. "This survey underscores their influence as ultimate information resources for sophisticated shoppers, and accordingly we urge manufacturers to strengthen their online knowledge bases and enhance the content they share with their retail and search engine partners."