A record number of concurrent users were on the service during the first day of 2015.
A record for the most active users at any one time on Steam has been set this week. On 28th December there were a huge 8,357,541 concurrent users online on Steam.
It's not hard to see huge numbers of Steam users flocking to the service at the same time around the festive period, with the Steam sales happening and all that. But, as that new record was set, another new record came just a few days later, on New Year's Day - the service recorded 8,466,441 concurrent users online.
On that day the most played games were Dota 2, Counter Strike: GO, Team Fortress 2, Football Manager 15, and Skyrim.
Unfortunately the Steam Holiday Sale has ended now, so hopefully you picked up enough games to occupy your time until another sale pops up.