Steam, Valve's PC gaming haven, was unavailable to users Friday morning after the site fell victim to a reported distributed denial of service (DDoS) attack. Two Twitter users claimed responsibility for Steamís service outages, saying they used a botnet to overwhelm Steamís servers with traffic.

The outage comes on the last day of Steamís holiday sale that began on December 19 and ends at 1 PM Eastern/ 10 AM Pacific Friday. For the final hours of the sale, Steam was offering the most popular deals from the 15 day holiday sale.

Steam was definitely struggling to stay online Friday morning.

As usual when online outages happen, Steam fans took to social networks such as Facebook and Twitter to vent their frustrations over the service outage. Some hoped Steam would extend the sale as a result of the outage, while others were growing frustrated that they couldnít access Steam services.

But whether Fridayís outages were actually the work of hackers or Steamís own IT support has yet to be determined. Despite the hackersí claims, Friday wasnít the first time Steam struggled to stay up this holiday season.

Valve set off a flood of Steam traffic on Christmas Day when it offered Left 4 Dead 2, the popular zombie shooter from 2009, as a free download. Steamís servers struggled to handle the load from so many people grabbing the freebie at the same time and many users reported the site was inaccessible to them for brief periods that day.

But the service woes didn't begin and end with Steam: EA's Origin platform, Blizzard's, and the servers for both League of Legends and Dota 2 also battled DDoS-related outages in recent days, though those attacks were claimed by another hacking group.