Alfresco, my employer, is based in London, so I go over once per quarter for management meetings. Because I'm there so often, I took the time to get an Oyster card, which manages payments while riding on London's public transport. Little did I know that Linux enables my transfers from Paddington to Arsenal Tube Station....
As ZDNet reports, Transport for London opted for Linux to remove its fetters to proprietary systems that had been crimping its ability to innovate:
The Oyster contactless card system...[previously] suffered from lock-in to proprietary systems, which hindered developments to the online payment systems...."The hosting was on a proprietary system, centred on one application....It demanded certain hardware, and was locked into one design of infrastructure."
With open-source Linux, however, the system is open for London to take the system in any direction required, without concern for some proprietary vendor holding its system for ransom. Why would any public agency lock itself into a proprietary vendor? For that matter, why would anyone?