Microsoft will release prototype implementations for HTML5 features that are currently in flux.
MS is opting to provide stability in the full release while giving optional prototype implementations to help test out the standards.
For features that aren't yet "site-ready," Microsoft is using a system of prototype implementations.
The prototype implementations of unstable specifications, for example, will eventually reach Redmond's "site ready" threshold, and they will probably do so within six months.
A prototype implementation was developed in 1995 by Eiffel Software.
Net (prototype implementation, not officially supported yet).
The project is tasked with developing methods for data analysis, visual search systems, metadata-based searching and prototype implementation.
A prototype implementation can be found at http://eap-ikev2.sourceforge.net.
The topic of my talk was our prototype implementation of the Digital Public Space.
A prototype implementation of the ParaSail compiler and virtual machine is available.