A recommendation server is provided. The recommendation server includes a communicator configured to receive, from a first device, when a first user's input for communicating with a second user is received by the first device of the first user, a transmission request with respect to a list of a plurality of items of content related to an operation of the first device which was performed when the first user and the second user met each other; and a controller configured to determine a time when the first user and the second user met each other, based on at least one of first user's activity information of the first user and second user's activity information of the second user, and to provide, to the first device, a list of a plurality of items of content related to an operation of the first device which was performed at the determined time.