The Web is but yet another kind of coarse-grained client/server crap, where the reader is on a terminal (that displays a layout text document from HTML input, instead of a raw character array from VT100 codes) and is denied any computation power, while only the server-writer can put anything to the document. To achieve meta-browsing through the WWW, we oughto rewrite a full reflective OS on the server side, that must cope with a stupid horrible unexpressive HTML language as its only interface. Yuck.
Also, using URLs is like having to work with pointers, not objects, in an environment with an unreliable buggy moving GC. It just can't work, so that a reliable meta-browsing server on the WWW cannot include meta-browsable external references.
To sum it up, the WWW is NOT a meta-browsing system,
just a "hyper-browsing" system.
"Hyper-browsing" only allows browsing in multilinear ways,
which is not better (though often faster) than a book with a good index.
The rare cases of interaction in the WWW are very limited,
and the reader is completely subject to the publisher as for this interaction.
On the opposite side,
Tunes is a "Meta-browsing" system,
that allows arbitrary extraction of information
from the document view as a semantically meaningful object
instead of a meaningless syntactical stream of bits.