github, social networks, ddos, hackers, hackingGitHub, a site for sharing open-source software, was hit with a denial-of-service attack Thursday afternoon that seriously impaired its performance for more than half an hour, according to the website.

A denial-of-service attack occurs when a group of people overwhelms a site’s servers by attempting to access the site simultaneously. A GitHub spokesperson said the company didn’t have any information on who was targeting the website.

GitHub, which supports open-source software, would be an unusual target for well known hacker groups like Anonymous, who generally express a libertarian political viewpoint that is generally consistent with open source technology.

GitHub is a for-profit company, however. It generates revenue by charging users who host software that isn’t open source.