Dell has a dedicated team of around 40 people that interacts with consumers through its blogs, community forums and third-party sites. The company began its social media push last year as it moved to repair its public image.
"There's been a realization over the last several years that your customers are going to talk about you online and you have a choice to join that conversation," spokeswoman Caroline Dietz said.
Dell said it has used Twitter to sell $500,000 worth of refurbished PCs. The company also took ideas solicited from its IdeaStorm site to make changes to its Latitude laptop.
NetApp sells data storage equipment only to enterprises, so its strategy is more limited. Its employees are encouraged to blog on third-party sites about its products and the company focuses on keeping a unified message.
Still, NetApp said that, for the first time, it is dedicating 20 percent of its PR budget to social media.
One of the most effective social media advertising strategies, said author and blogger Dave Taylor, is to simply hand a new product over to a blogger for a test-drive.
A bad review can hurt, but an endorsement from an established name "makes for some powerful marketing," he said.
In a similar vein, hard-drive maker Seagate Technology sponsored prominent blogger Robert Scoble, who wrote about the company's products and took part in promotions.
Seagate news now goes up on Facebook, pictures of products go on photo-sharing site Flickr, along with Twitter tweets. The company has even built a studio to film Web videos.
Although some companies may balk at the idea of relinquishing control of their message, they may have no choice.
"Historically, companies have been really focused on controlling the information they disseminate ... and the fact is that's dying, because accessibility and communication have so dramatically increased and improved," Taylor added.