This is a splendid idea, because if there's anything a chess website needs, it's a way to project xenophobia. How about filtering by age or, better, gender too? We do have women-only OTB-tournaments, or children-only OTB tournaments, so it only makes sense, right?
(for those unable to read, this is sarcasm)
Funny how people only discuss the techical difficulties (of which there are next to none).
And will the site change the number of genders every time a new gender pops up?
Can we sort by height? Weight? And will there by a report button when someone gets bent that no one would play then because of their weight?
What about the size of someones nose?
What about amputees?
If those were things that people wanted to sort by I suppose so. But I don't think the option currently exists to put things like weight, height, nose size, etc on a players profile. And as someone else pointed out, even if they did, they could by lying.
But rating, and IP address and country flag are things that are identifiable, even if they are not always accurate. So if people want to sort opponents based on that, why not allow it?
The rating filter has a reason to exist, because it can balance the game based on user preferences. Blocking specific nationalities doesn't have a logical reason to exist nor to balance online games in any way, therefore is an irrelevant filter to implement.
I guess that depends on who gets to decide what logical is. Is it logical that people choose to play against only their friends and not strangers? Is it logical that people choose to play only black, and prefer not to play white? Is it logical that people choose to play only people rated below them?
That's the problem with people, they are always wanting to do something someone else doesn't agree with. I don't see the harm in allowing people the ability to choose whom they play with, regardless of their reason.