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,) 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 ofandonce Valve shared the numbers and thinking behind the games.Here are the best tweets from today, arranged for readability: