On reflection, the telcos do give us an interesting model for what PaaS *could* be like, and a metaphor for types of cloud services. To wit:
- As users, we don't know (or care) where the carrier's gear is, or what platform it's based on so long as our calls are connected and our voicemail is available.
- There isn't technical "lock-in" as we think of it. Your address (phone number) is now portable between carriers, and the cloud "API" is the dial tone plus those DTMF touch-tones
- I can "mash-up" applications such as Voicemail from one company, conference calling from another, and FAX transmission from a third.
- There are even forms of "internal clouds" in this model -- they're called PBXs (private branch exchanges) which are nothing more than "internal" phone switches for your business
Similarly, many enterprises will need to retain 100% control of certain computing processes and never outsource to a cloud; They'll certainly be attracted to the economics that external computing resources offer, but will eventually build (or acquire) a similar *internal* capability. Just wait.