With the question in mind what really constitutes a “virtual museum” one can simply ask the search engines and soon will be brought to “virtualmuseum.ca“, which calls itself “The largest digital source of stories and experiences shared by Canada’s museums and heritage organizations”. In effect, this is a huge collection of 630 virtual exhibits with the oldest dating back to 2001 and it brings together “content from close to 1600 museums, educational institutions and the private sector”.
To make it short: There is no definition by words for virtual museum given on the page, it is basically a collection of exhibits plus educational material – but, in a sense, the limitation to virtual exhibits and education might be seen a bit as a definition.
The exhibits in this collection can be sorted by date of publication resulting in a good demonstration of developments during the last 15 years. Some of the oldest exhibitions ask the user to install Quicktime 5, others ask for installation of flash-players, the older exhibits use very small fonts on a very limited section of modern screens while the newer exhibits don’t ask for installation of software and come with responsive design using big letters. Seen this way virtualmuseum.ca is a good source for those trying to understand developments in technology, content and presentation of “virtual museums” – even if the latest developments with 3-D, holograms etc. are not reflected here.