For starters, just the fact that Skype is thinking of SIP as the alternative to JoltID is a good sign. It brings all kinds of attention to something that has been taken for granted and not given the kind of respect it deserves.
That makes it great news for the industry, and for companies like clients VoxBone and HiDefConferencing both of which play heavily in the Skype ecosystem, but are very much SIP based. It's also welcome news for client Junction Networks as their OnSip platform is business grade and far more developed and live than anything Gizmo has revealed so far. Likewise it's great news for client Truphone whose all SIP infrastructure is immediately interoperable with whatever the new Skype becomes. It's also good for client iotum (and blogger Alec Saunders) whose patent portfolio includes some very nifty feature sets. Same for ifByPhone which would immediately see a huge market open up in terminating their suite of automated telephony applications' calls to Skype via SIP in addition to 800 and local DIDs. This is also equally great for client xConnect, who SIP based peering platform and application ready architecture means Skype doesn't have to look far for a lot of interconnection simplicity.
Take OnSip for example. Here's a business grade, market proven (and loved) SIP based hosted PBX play built from the ground up by Junction Networks. They have a fully SIP compliant infrastructure, they are running minutes every hour of every day, with termination to SIP and PSTN networks, and have developed an entire web based UI that lets their customer manage calls at the individual user level, as well as a full backend customer administration portal. With their open source heritage making it possible to do almost anything imaginable, there's not much that Gizmo has that's different. As a matter of fact other than the downloads (which are not users) that Gizmo has, its possible that OnSip has even more active end points on a daily basis and may be terminating more calls to more endpoints that aren't all OnNet. So if Skype buys SipPhone/Gizmo this means all the OnSip customers can call their Skype pals without any hassle, or a need to have a second softclient running...That means greater efficiency, further reach and all the services that can run on SIP take the front seat over minutes.
Now lets look at who else this is good for. Companies with rich understanding of APIs like Voxygen and Thomas Howe. Voxeo, Cloudvox, Twilio, Broadsoft, etc. The list goes on and on. What's more all the current SIP customers of CallCentric, Inphonex and other Internet Telephony Service Providers instantly make calls to Skype ID's for Free from a SIP client or endpoint. Any SIP client or Any SIP endpoint. The list goes on and on.
Oh, and yes. It is good for Gizmo and founder Michael Robertson too.