Computable Document Format

[Krisidious]

http://demonstrations.wolfram.com/download-cdf-player.html
Computable Document Format (CDF)
Documents come alive with the power of computation
Powering the next generation of interactive documents, blogs, reports,
presentations, articles, books, courseware, information and knowledge
applications, and more.

[Aerilius]

If interested then in the documentation

[Trogluddite]

Looks very intriguing.
If it could become as ubiquitous as .pdf's, it looks like an ideal format for presenting product proposals, user guides and tutorials.