web interfaces
Web interfaces (that is, interfaces built using web technologies) can be quite useful -- even for local applications, with no network connectivity necessary. I have seen quite a few native GUI applications whose interfaces could be greatly improved by turning them into web interfaces.
There are, as you point out, a great many cases where connectivity should never be a requirement for the application, though. Thus, my differentiation between web interfaces and web applications, where the core application itself depends on a webserver -- in part because building an application on top of a webserver is an exercise in stupidity when you do not have a network-connected intent for the application itself. Using HTTP to connect the interface to the rest of the application is a terrible idea if you are not dealing with situations where the application and its interface are not on the same machine.
Of course, web interfaces are not always appropriate regardless of what's behind the interface. Local native GUI applications can serve as clients for remote network applications as well as self-contained local applications, and sometimes that sort of interface is better than the web interface. There are cases where a console-based interface is by far the best option, and web technologies do not yet offer the kind of capabilities of user shells and other terminal console technologies that make them such a great place to use some applications and utilities. For instance, I wouldn't want to try to do all my software development inside a vi-like editor interface that is, in turn, embedded in Firefox.
I loathe telephones, in general, by the way. I do, however, conduct a lot of business online, and find IMs, email, and IRC (in no particular order) quite useful for such purposes, to say nothing of some of the discussions here at TR and on reddit.
