I first became interested in what eBay was doing with its data centers during an Uptime Institute conference two years ago. I was struck by the company's data center guru, Dean Nelson, concise argument tying his company's data center efficiency to eBay's long term business survival. More recently, I interviewed Nelson (who is eBay’s Vice President of Global Foundation Services, notice the word data center isn't even in his title) about a massive modular data center project on top of a building in the Arizona desert. The resulting post, "5 green data center tips from Project Mercury," convinced me that Nelson would be a great guest for a ZDNet "Hot Topics" webcast. The resulting conversation "Is Modular Design the Secret to Data Center Efficiency?" explores the potential of data centers that deployed in a modular or container format.