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If I purchase a subscription for a friend will deviantART notify them?
Yes.
If you buy it for a friend, you receive an email, letting you know it has been activated, and your friend receives one as well, letting them know how long it is for, and that you bought it for them.
Note: You must have an up to date email address to receive confirmations. We cannot re-send confirmation emails since they're auto generated by the server at the time of purchase.