To fulfil the vision of software as a service, Web services will need to be built primarily from software components and elements that must be identified, located, accessed, and dynamically assembled into customisable turnkey applications, IDC said. This vision cannot be implemented in its entirety using current technologies and application development methodologies, according to IDC.
Additionally, the need for Web services to share components and data raises difficult business, legal, and contractual issues. IDC believes Web services may never achieve the full-scale magnitude envisioned by proponents.
"There's been a lot of hype and expectations set [regarding] the capabilities of what Web services can achieve," said IDC research director and author of the report, Rikki Kirzner.
"Some of that is achievable today, some will be achievable in three to five years, and some will never be achievable," Kirzner said.
Today, Web services provide integration. In three to five years, Web services will support software as services behind a firewall or on a private network, Kirzner said. The more sophisticated uses - the pulling together of software to provide a customised application - is years away, if it ever happens at all, she said.
Obstacles to implementation include creating software as services based on components from third parties, the fundamental changes users will have to make in how they view software assets and intellectual property rights, semantics, standards, security, and privacy issues.
Despite the challenges, the concept of Web services provides a compelling way for IT to become more responsive and adaptable to changing business requirements, IDC said. But Web services goals must be realistic.
An official at BEA Systems, which participates in the Web Services Interoperability Organisation, said he agreed with the report to some extent about the limitations of Web services.
"I think the first sentence, where IDC says Web services are proving their value today, we absolutely totally agree with that," said John Kiger, director of Web services marketing for BEA. Users are already delivering software as services today, he added.
"I think what IDC is talking about [in noting limitations] is pushing this vision of an Internet filled with Web services components where businesses locate and dynamically create business relationships, dynamically accessing these Web services over the Internet. What we believe is that vision in its most grandiose form fails to take into account the fundamentals of business relationships," Kiger said.
Business relationships are based on trust and assumed or explicit levels of service, which do not happen through dynamic creation of these relationships, Kiger said. For example, an airline would not dynamically contract through the Web for jet fuel; it would want knowledge of the fuel supplier's capabilities, he said.