Over the last 15 years or so, I've seen an evolution of conferences into various spaces, from beginners introductions to in-depth training on various technologies. What's often missing is the view from the trenches - the insider tips on what works and what doesn't, and what to do with the inevitable failures happen.
The big value of Surge was these tips and techniques - not "tricks" by a long shot - backed by unabashed stories of failures and how they were recovered from, as well as stories of building big infrastructures based on those lessons, and how they endure real-world situations.
From the multi-million-user websites, to much smaller installations, the issues of scalability were discussed and practical recommendations made, but no silver bullets offered, as the consistent message was that you must have a deep understanding of your installation, complete with many metrics over time, and a grasp of how those metrics interrelate.
The high point for me was John Allspaw's discussion of Etsy's procedure for rolling out new features safely, planning for failure, and measuring success.