Google Health and Microsoft Vault are the two most notable players in the HIE field. The long-term goal of which is to improve patient care through improved communications between stakeholders. Presumably, improved efficiency equates to lower costs. The current push to HIE's is being facilitated by growth of Web 2.0, improved interoperability of disparate systems and improved connectivity.
Unfortunately, HIE also face some major obstacles not the least of which is standardizing different systems. Web 2.0 seems to be quickly providing the tools to allow communication. The ultimate goal of better care at a lower cost has not been proven so the economic viability HIE's remain in limbo. If an average person visits their family doctors 2.7 times a year, how much would they be will to pay for electronic access to their records? Also, IT system providers are notoriously protective of their code. Unless there is a major consumer push to have access, competitive advantage will not compromised for improved portability.
HIE's are a long term goal for the Health care IT community. The tools are just now coming of age to facilitate the transition but only time will tell if these is a transition in the way health records are maintained or simply another tool looking for a purpose.