I, like Miriam, thought this dating locally thing on Slate was pretty good and clever. It's just another case against long-distance relationships. Now I'm not totally anti. I know that a lot of people are strongly committed to someone and may need to go through periods where they aren't located in the same city, state, or country. But I would dispense this advice to anyone who's considering such a long-distance endeavor: If there's not a defined end point to the long-distance part of the relationship, don't bother.
I know it's not that simple, but I've seen too many people carry on long-distance relationships with an indefinite end point end end badly. It may seem weird, but there's a lot of commonality about living in the same place and seeing one another often. So as Miriam pointed out, not only is dating locally good for your emotional health, it seems to be good* for the environment.
*I know all relationships aren't the same an you should in no way interpret this to mean that if this situation applies to you I think you are dumb or your relationship is doomed. There are exceptions to every piece of relationship advice.