Great question — answering as the UphillTech team:
If there is basically no additional content on these pages they are very thin. Basicly product pages would have more than just a price, they would also list features, etc, and they are to thin much of the time. And thin pages don't do well until you fatten them up with content. You may even want to no index those pages until they get fatter. You could make a fat, "javascript developer salary calculator," telling people where the best places to be a javascript developer are so Austin Texas may be included on the category page as a trending location. ... then fatten up the city pages comparing things like (companies that hire javascript developers, how well freelancers are doing, cost of...
Full answer by Wayne Smith: https://webmasters.stackexchange.com/a/140875 (CC BY-SA 4.0).
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