Certainly Skype is not a walled garden. All things being relative, it's certainly not overly closed either.
What tipped me over to share personal opinions in public was an article by friend Jon Arnold.
A particular comment struck me, which was:
While it's easy to write them off as an out-of-synch walled garden...In the case of Jon's article it was just more implicit propagation of the false notion that Skype is a "walled garden."
It would be good to debate such notions if need be; I'd hate to think that in 2009 we get more drip-drip of false notions by bloggers and press. Therefore I'd love to have feedback in the form of comments and/or blog responses on any of the opinions below.
Claims that Skype is a "walled garden" because the team decided that the SIP signaling "standard" was not suitable is absurd. Note that later on Google had similar sentiment (hence the development of Jingle) for Google Talk.
For the sake of discussion, the best example is the "Skype-clone" Gizmo5. Being a clone and therefore later into the game, Gizmo had to have plans to differentiate itself. The chosen differentiation plan was to tout Gizmo as "open" and to knock Skype publicly on an ongoing basis for not being "open." I believe that such a campaign has only been fueled from a public relations perspective. I may even consider that the intention was good. But the reality is it actually lacks a solid technical or visionary underpinning.
The founder of Gizmo5 stated vehemently for example that:
Skype has a closed network.I cannot understand such a statement using Gizmo5 as the benchmark. With Gizmo5 you cannot build a true peer because the source code is not available. Its method of establishing the P2P overlay is proprietary and so without the source code you cannot build a true peer (it does not use the open P2P SIP standard). Therefore using the same yard stick used to denounce Skype as closed, Gizmo5 is also a "closed network."
Maybe the founder thinks that it's open because it supports the SIP URI names/address space? But I think that would be a weak argument for two main reasons. Firstly because Skype supports not only the private Skype namespace (i.e. a Skype ID) but also the E.164 namespace (i.e. telephone numbers). There is little consumer demand for the additional support of the SIP URI space.
Furthermore the foundation of such an argument would be wrong because it's assuming that we are extending Alexander Graham Bell's system onto IP; i.e. Skype is a telephone and therefore ought to interoperate telephony calls into as many name/address spaces as possible in order to be as open as possible. That is quite wrong because Skype is multi-modal for a start. For folks who really want to stretch the argument they might say they want Skype to interoperate all the modes from presence to video to file transfer (and somehow keep the end-to-end encryption somehow intact). Again I'd say that is an unfair request because it's a huge technical hurdle and there is near-zero consumer demand. But worse still, it's assuming that Skype remains fixed as just being a multi-modal client; what if it starts adding social networking profiles and letting you see friends of friends for example? In short if you want Skype to continue as an experiment in communications innovation, don't start locking it to being any one thing, by demanding full interop.
Another statement made was
Skype operates the largest closed calling network on the planet.This seems illogical. You can call telephone numbers, receive calls from telephones AND call between those in the Skype ID namespace. So it's an even larger calling network than the PSTN by being a superset!
And finally another statement was:
Skype continues to deny Gizmo5 and others in the internet calling world the information and access to allow calls to flow to and from your network.Again I completely fail to see this. You can call between Skype and Gizmo using the E.164 namespace. I see no reason Skype should have to support the SIP URI namespace to help bolster a competitor! But again, this argument completely lacks vision of the long term evolution in communications, sticking to telephony calls over IP (yawn) being the future.
It's also worth noting that the default Gizmo setting is to use a proprietary Codec - quite simply because it's far ahead of an open source version.
I'd therefore conclude that all things being relative, Skype does not deserve the label "closed."
It's a shame the word "open" seems to be able to conjure up sentiment to such an extent that rationale is dropped. Lets have some sense for 2009 and drop such claims! "Open" is great where it can accelerate innovation. But lets guard against having the term thrown about just as "PR fodder."
Now turning to the phrase "walled garden." This is a term used in telecoms when a majority of subscribers are restricted from doing what they want; for example sharing of ringtones via Bluetooth, using WiFi from a PDA, having access to all Web sites etc. Not using the SIP URI namespace, when the user demand for it is near-zero does not therefore warrant the term "walled garden" being applied.
In summary Skype is not a walled garden and all things being relative, is not closed either.