store一般是指规模比较大的仓储式商店或百货公司.例如：Most department stores have big sales before Christmas in the US.（在美国,圣诞节前夕,多数百货公司都有大优惠.）She buys a chair at the depart-ment store.（她在百货公司买了一把椅子.）
而shop一般指小型商店或小商铺等.例如：There are many new houses and shops along the street.（沿街有许多房屋和店铺.）Is there a cake shop nearby?（请问附近有没有西饼店?）
看来不一定用哪个,看情况,大多数是taobao shops
