For the record, Civilization (I think civ3) had outpost, for precisely this purpose - to let you use resources without the need to build cities. Later installations scrapped the concept.
That said, I like them too. I did not pay close attention to my pioneer first time I played and accidentally founded an outpost instead of my first city, and then waited forever for it to grow to a city I thought the concept was similar to MoM, where newly founded cities has an outpost phase.
Building them, however, should be cheaper than building a city.