The bulb itself is an NEMA A21-style bulb, with an E26d style base. It will be 134.9 mm long, 28.2mm wide at the base. The height of the conductor screw will be 24.4mm. As indicated, this is a three-way bulb, rated at 50W, 100W and 150W.

As you can see, the inputs and outputs of the lamp are heavily-constrained by a number of standards. Is this a bad thing? Is the consumer deprived for not having to worry about different plug and outlet types, or what gauge cord to use for their lamp, or what thread connection to use? On the contrary, it is a blessing for the consumer that such pieces are interchangeable commodities.
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It is the same thing with document formats. Consumers don't want to worry about document formats. They don't want to even think about document formats. They just want them to work, invisibly, without problems. Of course consumers want choice, but it is the choice of applications, choice of features, choice of vendors, choice of support options, choice of open source versus proprietary source, choice of heavy weight versus web-based, a choice of buying a single application versus buying a suite, etc. A single universal file format is what makes these other choices possible, just like a choice of the Medium Edison Screw bulb leads to an affordable choice in lamp designs.

This is where identity standards like WS-Trust enable identity interoperability across a whole range of endpoint solutions, smart cards, cellphones, federated directories, and so on. The consumer's identity form factor will be determined by many things - technical limitations, device constraints, organizational policy, usability and so on, but the real software architecture problem is how do you move identity information around, protect it and recognize it. No one identity standard is sufficient for all use cases. You have an OpenId endpoint, I have a X.509 endpoint, and we need to traverse a SAML-based infrastructure, we need something to plug all these together.