The OP quoted Spolsky mentioning “a feature... for dentists”. That’s one example of a vertical market.
My last employer made a search engine specialized for geography: government agencies and energy companies (two other vertical markets) paid beaucoup bucks for it. (Not beaucoup enough to satisfy the VCs, alas, but the product itself is still being sold by another company.)
My last employer made a search engine specialized for geography: government agencies and energy companies (two other vertical markets) paid beaucoup bucks for it. (Not beaucoup enough to satisfy the VCs, alas, but the product itself is still being sold by another company.)