1. Memory storing instructions executable by a logic subsystem including a computer processor to perform: receive a share command indicating a digital content item that is recognized by a digital content management service and that is to be recommended; receive an indication of an intended recipient of the digital content item; responsive to receiving the indication of the intended recipient, determine if the intended recipient belongs to the digital content management service via a database comparison in which an address of the intended recipient is tested; and if the intended recipient belongs to the digital content management service: build an in-service content-recommendation message for the digital content item; and send the in-service content-recommendation message to the intended recipient without sending an out-of-service content recommendation message to the intended recipient; and if the intended recipient does not belong to the digital content management service: build an out-of-service content-recommendation message for the digital content item; and send the out-of-service content-recommendation message to the intended recipient without sending the in-service content-recommendation message to the intended recipient.