An information processing system includes a memory, a content display, an extraction unit, and a message display. The memory stores multiple pieces of content and multiple messages transmitted by multiple users. The content display displays the multiple pieces of content. The extraction unit extracts multiple messages from the memory if a user selects at least one piece of content of the multiple displayed pieces of content. The multiple extracted messages refer to the at least one piece of content or have the at least one piece of content attached to the multiple extracted messages. The message display displays the multiple messages extracted by the extraction unit.