In my local community, when you turned 14/15, you were off down the pub where most of the other residents of the community were. It was great. Everybody was from the same area and class, meaning you could understand and relate to any issue or talking point because everybody had shared similar experiences. It was the hub of the community. That's similar to the way I see City, although on a slightly larger scale.
I don't think it is ever accurate to say that, because somebody grew up in Manchester, they love the club more than someone who grew up in Ottawa. Many people that I know won't be as dedicated as someone who wakes up at 5 in the morning to watch City on the telly. However, I do think that those who grew up around the club, and declared their allegiances to City in bad times, have a greater feeling of what City means to the Manchester community - I don't think you can get that from reading Wikipedia or a Gary James book (no offence Gary).
Obviously, as City expands, more and more people will fall in love with the club. That also means we will get some here who pick and choose when they are a Mancunian. I think there's something exceptionally shallow about that and I take issue with it.
With that said, every person who goes to great lengths to watch City and post about City on a daily basis is part of the community - and I love them for that. As idealistic as it may be, I also think that if you are not from Manchester, you should put something back into your community by supporting your local club and microculture, too. If they have just got going, I would rather you spent your money there than on City; and if everything goes well, they might be like City in another three generations.