My dictionary says a museum is "A building used for storing and exhibition
 of objects...". Not much exhibiting going on in this "museum". I think a
 museum is only a museum if the public can go there and see the physical
 objects. I don't think a web site can be a museum, unless the "objects" are
 software or other purely digital artefacts.
 
However, definitions change, and dictionaries will lag behind technology
almost by definition.
Is Amazon a store?
Marcin