Initially: Unidirectional data transfer (server sends page to browser)
Increasingly: WWW as a single application with many components:
Increase in data transfers among servers, proxies, and clients
Increase of cases where non-ASCII characters are allowed (due to Unicode/ISO
Increase in data transfers between different protocol/format elements (such
as element/attribute names, URI components, and textual content)
Definition of specifications for APIs (e.g.