Vaporware is a term used to describe a product, usually software, that has been announced by a developer during or before its development and, therefore, may never actually be released.[1] The term is usually applied to products which fail to emerge after having well-exceeded the period of development time that was initially claimed or would normally be expected for the development cycle of a similar product. The term implies unwarranted optimism, an as yet unannounced abandonment of a project, or sometimes even deception; that is, it may imply that the announcer knows that product development is in too early a stage to support responsible statements about its completion date, feature set, or even feasibility. However, most vaporware would not be considered a hoax since the makers have a genuine intention to create their product, even if it ultimately never materializes. Products with unspecified release dates or long development times that outwardly demonstrate regular, verifiable progress in production are not normally labelled vaporware.

- wikipedia

so UMD and PC are technically right but semantically incorrect, everyone else is semantically correct but technically on dubious ground.

Pedantics are fun!