I agree. GMail and Google Maps showed a complete different web but XMLHttpRequest was needed for that and was a milestone even if there was no web app to show at that time.

We should also take into account that Flash [1] was the technology that ate the limitations of the web. Flash was really powerful. More in a moment with low bandwidths around the world. For example this late 90 animation would be impossible to stream [2].

[1] https://en.wikipedia.org/wiki/Adobe_Flash

[2] http://swain.webframe.org/zeek.html (SWF files) available for streaming in YouTube: https://www.youtube.com/results?search_query=zeek+locomotion