Online DVD rental leader Netflix Inc. resumed normal shipments Friday after its distribution centers were crippled by three days of severe technical problems, a spokesman said.

The Los Gatos-based company also offered a 15 percent credit to customers whose discs were delayed by the outage, the longest disruption in service since Netflix launched its subscription service nine years ago.

The outage held up shipments for about a third of the company's 8.4 million subscribers, meaning the total value of the credits could run into the millions of dollars.

The credits will automatically appear on customers' next billing statement, according to Netflix spokesman Steve Swasey.

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People who were trying out Netflix with its two-week free trial offer will have the trial period extended by one week if their shipments were held up.

The company has declined to say what caused the outage, which affected all 55 of Netflix's shipping centers. Netflix was able to ship some discs Wednesday and Thursday but none on Tuesday, when the problem was first disclosed.

The last time Netflix had a major outage was in March, when the Web site went down for about 11 hours and caused Netflix to halt DVD deliveries for an entire day for the first time. Before that, the site had gone down for 18 hours in July 2007.

Netflix has won praise from some customers for notifying them of a problem many didn't even notice and for proactively offering credits.