Markets

Individual Human Users

Ordinary Users

I have spent too little time categorizing those who would bother to use a system such as we seek here. We delve too quickly into the ultra paranoid versions of things.

Here are some virtues we can quote for fairly ordinary users:

An interface to your bank. It might contain an ordinary browser but bugs in that browser are unlikely to be exploited because data paths ensure that it never sees exogenous bits except from the bank. A few other tools may be safely used in this context.
A context in which to read signed docs, sign your own and remember how you got various public keys and what you think of them. This is already too far over the edge.
An Apartment like facility for installing apps from unknown regions. The user is not especially aware of this facility.
The default browsers and e-mail readers will be situated in a suspicious context. If the browser, obeying some foreign JavaScript program, asks to read a contacts file, a window with a badge will open and declare such and offer to provide a fake list, which might be empty.

Paranoids

Gossips

Security Experts

Presumably both white hats and black hats

Contractors

Some specialists do contract work for several competitors.

Military

Spooks

Politicians

(alas) Crooks

This makes illegal conspiracy too easy.

Political Dissidents

Impersonal Uses

Or computers without heads (no screen or keyboard)

Industrial Controls

Uranium Centrifuges: SCADA

Robot Controllers

Car Driving Computers

Few automotive engineers, even today, know how many computer there are in their cars.

Computers in Light Bulbs

Internet Servers

DNS

SMTP & POP & IMAP

Internet Routers

Video Cameras

Refrigerators

Maybe small display

Many Corporate Functions

These overlap with Internet servers programmed to serve a corporation.

Banks are especially sensitive.

Cloud Data Centers

Contexts may serve to separate customers as Virtual machines do now. This would avoid a whole layer of overhead.

etc.

You get the idea.

Outposts for Social Media

Facebook and Linkedin will both want space on your computer and they will ask for access that you will now have the power and knowledge to deny.

Money Apps

There are two sorts here depending on where your wealth record is kept; on your computer or “in the cloud”.