It would effect it greatly I think. As a community it wouldn't effect communication, but for buying and selling it would. I know that 95% of the people selling things here are Canadian, so if I'm looking at banners, or see someone selling something most times I assume it's Canadian. If a larger American presence became more abbundant, I wouldn't know if something being sold was Canadian or Americian. Also because of the fact that the industry's are so diffrent, the volume of Americian breeders vastly out number the Canadian breeders. So then we get to a point like it is with most other sites, finding a Canadian add with something for sale becomes much more troublesome. The other big problem being that getting herps across the border is a pain so not only does it become harder to find the adds that relate to Canadians, but we have to sift through a ton of other add or sites that are completly usless to us. Now if you do a search on something like Yahoo or goggle for lets use Ball python as an example. You are going to get TONS of sites selling Ball pythons, and I'll bet most of them are Americian. So the Americian breeder has a much greater exposure, so this site gives some exposure to the Canadian breeders.
I fail to see how because this is a Canadian site could make you feel unwelcome? That's like saying that a Canadian on an Americian site should feel unwelcomed. If a site is Americian, then of course the content is Americian, the vendors selling are americian and the people posting are Americian. This is a Canadian site, so the same applies, it doesn't mean that Americians aren't welcome it just means this is a Canadian site.
1.2.1 Ball Pythons
1.0 Cali King Snake (Weebl)
0.0.1 Black Breasted Leaf Turtle (Hootie)