Amazon in Halacha

Shabbos:
Is it permissible to place an order with one-day delivery on a Friday?
If a package arrives on Shabbos, is it permissible to open and use it?
Is it permissible to make an online purchase on Friday when it is already Shabbos in the seller’s time zone, knowing the seller is Jewish?
Is it permissible to keep an Amazon account active during Shabbos and Yom Tov?

Ratings:
Is it permissible to leave negative reviews on products?
Is it permissible to create positive, but fictitious reviews for your own products to enhance sales?

Can one purchase items during the nine days (items like clothes and Keilim that is forbidden to buy in those days), to be delivered after tisha b’av?
Can one purchase item prior to the nine day to be delivered during the nine days?
Can one purchase items on Chol Hamoed (that are forbidden to purchase on Chol Hamoed) to be delivered after Yom Tov?
Can one purchase Chometz on Chol Hamoed to be delivered after Pesach?

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