In the recent years, the Internet has become widely available--both as a worldwide federated network and as a
set of standard protocols. The Web has however long waited to be fitted with a data representation mechanism
suitable for automated transactions. HTML, by essence presentation oriented--and made inextensible by
design--proved inadequate for the development of automated web transactions. XML, on the other hand--as a
inherently more suitable to take over this role. XML was originally destined to document publishing. Its attached data typing mechanism (DTDs), although probably sufficient
for the original purpose of the language--proved inadequate for its new role as a middleware. The recent adoption of
XML Schemas has lifted this deficiency.
As we will discuss in Section 1.3, several novel XML-based technologies effectively allow the cost of integrating applications across corporate borders to be potentially decreased by several orders of magnitudes--and consequently make inter-enterprise integration much wider spread than it is today. If such a dramatic cost fall occurs, there is no reason why applications should be only integrated between existing business partners. The applications could as well be exposed to the web proactively, as a service for potential new partners to use, rendering effectively software a commodity.