@Crusty: As I generally use Bascom to programme AVR I can run soft I2C or SPI on nearly any pin.
The thing is that a lot of Arduino users are absolute beginners -- they just want to plug the shields in and have them work -- it comes as a big shock to some of them when they upgrade to a Mega and find that 1/2 of their shields no longer work.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.