By country, as far as I know, and I could very easily be wrong, as I mostly don't really like these, except maybe some chalga:
Romania has only manele, which is semi-traditional* and similar to chalga in Bulgaria, where it is less "traditional" that in it is in Romania. Bulgaria also has pop-"folk"*, which in the early 90's was influeced by the Serbian sound (as far as I know Serbia doesn't have styles similar to chalga or manele), as was laïka in Greece.
As for the sociological significance of these styles and their substyles, one could probably write a book about it... One thing I can say is that the fact that Romania has only one such style could be attributed to the unparaleled polarisation of society there, and anyone who doesn't want to be associated with manele there attempts to emulate a "western"-like sound, thus O-zone and such abominations. The case with Serbia is different as there turbofolk is not associated with the lower class, actually I don't know if you can talk about classes in Serbia at all, it's pretty much a kleptocracy.
The situations in Bulagria and Greece are different and well, more fuzzy.
*And of course, the various genres of actual Bulgarian folk music are completely unrelated to any of the genres we discuss here. Actually there's a lot more variation between Bulgarian folk genres that it is between these here; all these are practically the same genre in comparison. I even feel a bit dirty mentioning them in the same post, but I needed to make clear that the use of folk in their names is criminal.