Amazon issues credits, apology for Web outage

* Gives lengthy technical explanation for system failure

* Amazon.com shares up 0.3 percent

BOSTON, April 29 Amazon.com Inc (AMZN.O) apologized to customers for an outage at its Web hosting business that caused some websites to crash, saying it would credit them for their inconvenience.

Although Amazon.com is best known as one of the world's biggest shopping sites, it is also one of the largest provider of Web hosting services, an area where it competes with Google Inc (GOOG.O), Microsoft Corp (MSFT.O) and several smaller companies.

On April 21, services to some of its customers were disturbed because of technical problems that the company disclosed in a lengthy document released on Friday.

The company said in a blog posting of nearly 5,700 words that the bulk of its customers had their systems restored by April 24, but that a small amount of data had yet to be recovered.

"We want to apologize," the company said in the blog posting. "We know how critical our services are to our customers' businesses, and we will do everything we can to learn from this event and use it to drive improvement across our services."

Amazon.com said it would give affected customers a 10-day credit for their usage in affected systems.

The company's shares were up 0.3 percent at $195.71 in midday trading. (Reporting by Jim Finkle; Editing by Lisa Von Ahn)