The Vancouver - Seattle Area is pretty close in distance as this photo shows
http://i.imgur.com/e3SXesM.jpg
I remember when Futureshop expanded into the states they had a few stores in the seattle area and bellingham. A family friend of ours worked as a regional manager for FutureShop and lived here in Vancouver area with his territory being WA State.
My roommate worked for a Magazine that was aimed at Canadians in the Vancouver area but often worked out of the office in Lynden WA just across the border from Aldergrove.
3 women I used to work with all owned property at the same place at Mt Baker in WA state, they said it was majority of Canadian owners who had a place there.
at least 3 women I worked with at an old job dated and married guys from Seattle, they had lived both sides of the border and ended up settling in Canada. So cross border relationships are pretty common here.
There are a few businesses you will often see listing their locations as Abbotsford, Surrey, Bellingham.
There are some radio stations based out of WA state whose main audience is Canadians so all the ads are for Canadian businesses. Same with KVOS or MeTV, its home is in bellingham but its advertising market is Vancouver and Seattle. They have an office located here in Vancouver as well. Before it became MeTV they used to do some shows that were shot here in Vancouver, like on the street events going on type of show. They still do segments here in commercial breaks.