The one I am referring to is an abbreviation of Machine to Machine.
It's simply a communication mechanism between machines or devices. The communication is done with minimal or no human intervention, hence the term machine. If interested, Wikipedia has a much more elaborate definition here.
M2M is getting a lot of traction within the connected device community because it touches many industry verticals spanning from industrial, consumer, energy, automotive and medical to name a few. A simple use case of this technology is a vending machine that automatically sends a signal to remote vendor to restock, as and when needed. Another one can be a smart meter sending energy consumption to utility company through a wireless or wired connection thereby saving operational expenditure of sending a person to read the meter readings. The consumers, in this case, benefit because they'll be better educated about their energy consumption, will be able to control devices remotely. You can find a number of these use cases on the internet.
On the utility front, smart grid investment grants were awarded by President Barack Obama that does infuse capital to bolster the utility use cases of M2M.
In a connected home, a residential gateway equipped with M2M protocols can play the role of deploying, maintaining and monitoring service/applications. Amongst others, these include remote monitoring for security, smart metering, e-health.
From a software stand point, M2M capable devices will have varying requirements ranging from simple low bit-rate connectivity, maintaining 99.999% availability, meeting the real time characteristics, minimal footprint, support for open source, etc. Multicore and Multi-OS's will also have a play here. If interested, my good friend Mark has been writing several educational posts on multicore here.
I would love to hear your comments because I am excited, are you?