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A roundup of the latest high-tech news “Hot Off the Wire” from The Associated Press and Local Tech Wire:

• WikiLeaks says source of U.S. documents unknown

LONDON — chief claims his organization doesn’t know who sent it some 91,000 secret U.S. military documents, telling journalists that the website is set up to hide the source of its data from those who receive it.

Editor-in-chief Julian Assange says the added layer of secrecy helps protect the site’s sources from spy agencies and hostile corporations. He acknowledged that the site’s anonymous submissions raised concerns about the authenticity of the material, but said the site has not yet been fooled by a bogus document.

Assange made the claim in a lengthy hour talk before London’s Frontline Club late Tuesday, in which he outlined the workings of WikiLeaks and defended its mission.

• GameStop buys social gaming website

NEW YORK — GameStop Corp., the world’s largest video game retailer, said Tuesday it will buy social gaming website Kongregate for an undisclosed sum in its latest step to expand its business beyond brick-and-mortar stores.

Kongregate has 10 million monthly players who use the site to play games and interact with one another. It makes money through advertising and microtransactions – charging small amounts of money for virtual items and extra content in games.

Kongregate will operate as a unit of GameStop and maintain its offices in San Francisco, said Grapevine, Texas-based GameStop. The acquisition is expected to close around Aug. 1. Kongregate’s co-founders, Jim and Emily Greer, will continue to lead the company.

The addition of Kongregate "is intended to hasten the transformation of GameStop’s website from a purely e-commerce site to a gaming platform," said Wedbush Morgan analyst Michael Pachter in a note to investors. The analyst estimates that GameStop paid between $12 million and $40 million for the site.

"At such a price, it is likely that the transaction is immaterial to the company’s results, and that any benefits are longer-term and strategic," Pachter said. He rates GameStop shares at "Outperform."

• IBM to pay 65-cent dividend

ARMONK, N.Y. – IBM Corp. (NYSE: IBM) said Tuesday it will pay its quarterly dividend of 65 cents per share on Sept. 10 to stockholders on record as of Aug. 10.

IBM announced in April that was raising its quarterly payout 18 percent from 55 cents a share. It has increased its dividend regularly over the past few years.