It's unconventional, but sometimes the Source engine is modded for purposes other than gameplay. Look over yonder. That's Frank Lloyd Wright's infamous Falling Water house, modelled in the Source engine. Fully realized physically, unlike any attempt that could be made in Second Life. It looks beautiful. To me at least, then again I am in love with the engine.
Actual house:
The Source engine version:
Not bad, eh?
Advantages: This would be an example of a Mirror World; it mimics an object in real life, virtually. This would probably be best used for virtual tours. I know there is a function in Source where commentary markers can be placed in locations referenced by their content. This would work well for anyone who could not actually visit the house.