This originated from a local tech blog who wanted to document locations that someone would be interested in finding in the tech industry. Places like the garage where the first Apple was built fits in this category. A geek was initially a way to direct folks to the right type of place. It's like the definition of porn is that I know it when I see it.
If we wanted to have a specific timeline, I would expect that the locations relate to the Information Age, so perhaps a more appropriate name would be to use this time period? The common theme is that the historical locations are based on this timeline and not all technological advances since the dawn of time.