Its value as an SSO is, I would think, unrelated to the number of personal connections on there. Metcalfe's Law does imply, however, that the social value (and likely monetary value) of Facebook is enormous.
An SSO really shouldn't be concerned with how many people are actively using it. It should be concerned with being a valid means of authentication for as many sites as possible such that it is a truly viable SSO.
Thanks, you made my day. I'll see you in hell
There's also the open source privacy scanner:
Canadian traffic laws are by province, though for the most part they're fairly identical as well. No right hand turns on a red light in Quebec.
Not really for personal use, unless you live in an area where owning a cellphone is prohibitively expensive and a landline isn't. I think the number of geeks that would fit this niche would be very small. Other than this case, I really think the landline is slowly going the way of the dodo as far as home users are concerned.
However, being able to push something like this out to business and corporate clients may well be a viable opportunity.
"More software projects have gone awry for lack of calendar time than for all other causes combined." -- Fred Brooks, Jr., _The Mythical Man Month_