Dell (Dell) says it has surpassed $3 million in sales attributed to Twitter, and the online social network, which has yet to make a profit, is watching closely.

Dell sells refurbished systems through Twitter at @DellOutlet, which the computer maker says has more than 600,000 followers. Since launching @DellOutlet in 2007, the company has taken in more than $2 million in sales directly attributed to Twitter, and another $1 million from people who start at Twitter and then move on to buy a new computer somewhere else on the Dell Web site, Stephanie Nelson, who manages the Twitter account, said in the corporate blog late Thursday night.

While not providing specifics, Nelson told USA Today that Twitter is soliciting feedback from Dell. In addition, the two companies are testing new features.

In making sales through @DellOutlet, Dell sends tweets to subscribers, telling bargain hunters the latest available refurbished systems. The company also messages couponhjs and clearance events.

The strategy has taken @DellOutlet to the top 50 most followed Twitter users, according to Dell. Such standings are tracked on a third-party Twitter monitoring service called TwitterCounter.

Other top 50 Twitter users includes brands like @Zappos, @Woot, @JetBlue and @WholeFoods. As of March, Twitter.com reached 9.3 million visitors, according to ComScore Media Metrix.