The first telecom arbitrage of the PC era was callback: a foreign caller would call a softswitch in the US, enter a destination, hang up, the software would call both the originator and the destination and bridge the two together.
Today an increasing number of consumers have softswitches in the home with VoIP services like Skype. But more people can use these services with the convenience of mobile phones that can leverge wifi, there is a need to phone home, or through home. This would let you route around last miles, captured locations and roaming long distances.
A personal softswitch would let you dial to your VoIP account, which in turn dials out to a final destination.
Of course, I called something the last telephony arbitrage before, and there may be others, so lets call this the final arbitrage.