[benkant]

We were writing web based GIS in 1996, using ESRI's MapObjects IMS. Tiling, projections, yes these were solved problems by then using available commercial software.

We were storing data in Oracle or DB/2 with ESRI's SDE sitting on top, because at that time no mainstream RDBMS had spatial types.

I don't recall if SDE supported SQL Server back then. That aside, you could have built TerraServer with COTS tech in 1997.

TerraServer was impressive due to being publically available. Nothing we built at the time was available to the public as far as I remember. But it existed.

And that's just web based stuff, which really is the easy part. Large scale GIS had been around for decades prior.