Back in ~2000, zipcode databases cost money, radius search was moderately difficult, and in the US Northeast, you can cross most states their edge-most "relatively major cities" in ~4-5 hours, putting an average distance of anywhere-to-anywhere in the state as ~2 hours. In the extreme Northeast (eg: NY, CT, MA, NH, VT, PA, NJ, DE, etc.) the whole state is ~1-2 hours "big", and likely concentrated in a single (or few) city centers.
Contrast to FL, TX, CA, and we had to immediately support zip-code-ish search (a non-trivial technical and operational burden, as zip-codes are rough-approximates for GEO's, and change pretty frequently) b/c "Couch for Sale in TX" means something completely different from "Couch for Sale in MA".
...you can see that "just tell me what state it's in" hits within ~1hr of a single city center up until you hit TX or FL. So in 2000 it was a reasonable shorthand for "east-coasters" to say: "MA == Boston of course", and "CO == Denver" b/c where else was the internet going to be? ...either relatively close-by, or at your states major population center.
This is totally non-scientific and anecdotal, but I worked for a P2P sales startup out of college, implemented the zip-code search, radius, and update code, and distinctly remember noticing that some competitors (and dating sites!) definitely didn't support zip + radius searching, and they were usually ones that were funded from NY. CA was probably a bit more technically advanced, geo-aware, and wouldn't usually launch w/o zip + radius capabilities... again b/c "Couch in NV/CA", or "Singles in NV/CA" is a completely different scale from "Couch in NY/NJ, or Singles in NY/NJ"
(edit: in the 2000-era!! barely dial-up, and computers in general were decidedly non-rural devices, no cellular networking, and a motorola "two-way" was peak connectivity).
Contrast to FL, TX, CA, and we had to immediately support zip-code-ish search (a non-trivial technical and operational burden, as zip-codes are rough-approximates for GEO's, and change pretty frequently) b/c "Couch for Sale in TX" means something completely different from "Couch for Sale in MA".
Contrast to the midwest (eg: kansas, montana), and this random-population-density-map I found: http://ecpmlangues.u-strasbg.fr/civilization/geography/US-ce...
...you can see that "just tell me what state it's in" hits within ~1hr of a single city center up until you hit TX or FL. So in 2000 it was a reasonable shorthand for "east-coasters" to say: "MA == Boston of course", and "CO == Denver" b/c where else was the internet going to be? ...either relatively close-by, or at your states major population center.
This is totally non-scientific and anecdotal, but I worked for a P2P sales startup out of college, implemented the zip-code search, radius, and update code, and distinctly remember noticing that some competitors (and dating sites!) definitely didn't support zip + radius searching, and they were usually ones that were funded from NY. CA was probably a bit more technically advanced, geo-aware, and wouldn't usually launch w/o zip + radius capabilities... again b/c "Couch in NV/CA", or "Singles in NV/CA" is a completely different scale from "Couch in NY/NJ, or Singles in NY/NJ"
(edit: in the 2000-era!! barely dial-up, and computers in general were decidedly non-rural devices, no cellular networking, and a motorola "two-way" was peak connectivity).