Valve Software's Steam Dev Days event was billed as a game industry-only, off-the-record event -- no journalists allowed. Fortunately, Valve has apparently been lax about the tweeting policy at the two-day Seattle event, as some of the 1,200 game developers in attendance have been quite chatty on social media, giving us a peek at what's happening on-site. In its second day, developers Tweeted plenty out of Valve's Steam Dev Days -- with the biggest buzz surrounding in-game economies (in particular, Team Fortress 2) and virtual reality, as both Valve's researcher Michael Abrash and Oculus co-founder Palmer Luckey took the stage to talk up the potential of the technology. While yesterday was consumed with excitement over the company's Steam Machines -- not least because Valve gave every attendee his or her own box, along with the latest revision of the prototype Steam Controller -- today the company was more forthcoming with information than giveaway items. Developers were awed by the success of Team Fortress 2 and Dota 2 once Valve shared the numbers and thinking behind the games. Here are the best tweets from today, arranged for readability: