A day after Facebook filed for its initial public offering, it’s Web site was inaccessible to many of its users Thursday afternoon for about 15 minutes.

There was no explanation of the downtime on the site's “Known Issues” page, though many users were reporting they were unable to access the site on — where else? — Twitter.

There was some indication that the brief outage was caused by foul play from Anonymous, according to tweets from Barrett Brown. Brown is the Dallas-based founder of an online think tank that works with Anonymous, and he retweeted a message from a Spanish-language Twitter account affiliated with Anonymous that reported Facebook was not accessible.

A part of Anonymous threatened that it would take Facebook down on Jan. 28, but that attack never happened. It should also be noted that when Facebook was hit with a brief outage last Wednesday, the Twitter account “YourAnonNews” seemed to take credit for the downtime, but Facebook told CNET that the downtime had nothing to do with any sort of attack.

“We pushed out code too aggressively sometime between 5 p.m. and 6 p.m. Everything is fine now,” a Facebook spokesman told CNET’s Chris Matyszczyk.

Facebook did not immediately reply to a request for comment on what may have caused the downtime Thursday.

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