What are the differences and similarities between 'urban' and 'rural' sociology?

What a timely question! I've been seeing similar musings popping up all over the place. In fact, I seem to remember an announcement that the Community and Urban Sociology Section of ASA has dedicated an open session at the 2012 meeting to asking how urban sociology methods or concepts might be taken beyond the city.

I think you've put your finger on the current points of overlap, too. There's a blossoming literature on rural gentrification, though some might counter that it's just a new term for an old phenomenon (counter-urbanization or deconcentration). I think what's notable, though, about applying the new term is all of the attendant theoretical connections it might inspire: Framed as gentrification, counter-urbanization becomes potentially problematic in new ways. Are urban-to-rural population streams the rural renaissance boosters dream of, or a threat to the ways of life (and cheap housing!) that rural residents often enjoy? Extending concepts or methods from urban sociology can, in that way, be very productive.

And so on the one hand, yes, there seems to be this new push to bring rural and urban sociology together (though I wonder whether this push is mostly unidirectional). But on the other hand, there have always been connections between the two. A hundred years ago, it was rural sociology, not urban sociology, calling for the unified study of urban and rural space. C.J. Galpin, who was at Wisconsin way back when, even coined the term "rurban" for what he say as an inextricably interwoven rural-urban system. Whence such holism?

Granted, historically, rural sociology has had close ties to the other agricultural sciences (e.g., ag econ). I think it's fair to say the field itself more accurately derives from there than from sociology. The first rural sociologists were protesting ag econ's lack of attention to the human element, not the lack of rural studies in sociology. And the stock answer today is to blame any lack of rural/urban dialogue on these associations and the land grant system, which directs at least some rural sociological research in a very particular direction (though such extension research also offers a model for a community-centered, locally aware sociology).

So yes, the two also seem quite distinct. Sure, there's plenty of overlap (check lists of past presidents of RSS and ASA, or participants at their annual meetings, and you'll find plenty of familiar names). But there are also separate histories, separate traditions, separate canons. And I think there's also an impulse to preserve academic territory: people stake out grounds and defend them as unique to preserve space for their own work, potentially to the detriment of seeing synergies and potential for collaboration. I'm not saying this is always mean-spirited or even intentional, just that it seems to be the way the profession--nay, professions--work. But despite these differences--or rather, because of them--there's ample opportunity now for rich cross-fertilization.

This question and ensuing discussion inspired a little notice on twitter and a connection with Anna Smith's (NYU) neat 'Developing Writers' blog on an earlier post of her's called "Define Urban, Please" : http://developingwriters.org/2011/10/18/define-urban-please/  

Interesting conversation there in the comments concerning the definition of "urban" (especially as relates to 'urban education'). Check it out!