I work on a daily basis in a house that was used as a Gestapo Headquarters during WW2. The authenticity of the place is therefore quite central in our permanent exhibition. I therefore find it very interesting to see how other historical sites use their authenticity when they publish digital exhibitions. Normally digital exhibitions are most about showing artifacts, documents and photos. An authentic site has another dimension to display.
On this background I will recommend to take a look at “The Secret Annex online” published by Anne Frank House in Amsterdam: http://www.annefrank.org/en/Subsites/Home/ This is an interesting way to try to implement the authenticity to a digital exhibition. Combined with the “digital walk” in the Anne Frank House, we also have the possibility to see historical documents and listen to a voice that teaches the historical context.
I am not quite sure how successful I find this digital exhibition. But it is an interesting way to exploit the authenticity of a building in a digital way.