I'm going to suggest that we move this page to Brotherhoods. Maybe it's just me, but "Fraternities" makes me think of those college organizations. This topic is definitely worth an article though. "Fraternities" is nice in that it would include "sisterhoods" as well, but it seems tome that Orthodox sisterhoods would have their own distinct but related history and characteristics, and would be worth a separate article. The "Orthodox Christian" part is redundant since that's the default for all the articles on OrthodoxWiki.
I note that Brotherhoods has been on the suggestions list for some time now, and that we already have an appropriate uber-category for such groups -- e.g. Fellowship_of_Orthodox_Christians_in_America is in Category:Organizations.