In John's Gospel, the beloved disciple's identity has long been a source of wide and varied speculation. Scholars have proposed everyone from Mary Magdalene (Scholars had speculated long before Dan Brown wrote The DaVinci Code) to Judas Iscariot. Traditionally John, son of Zebedee and brother of James, is believed to be the Beloved One and the eponymous writer of the Gospel. All indications would be that the Beloved Disciple was important to the early church community that produced this Gospel. This would make the Beloved Disciple akin to the "Teacher of Righteous" in the Dead Sea Scrolls. This would also explain the awkward ending in chapter 21 that indicates that the Beloved One somehow wrote the Gospel after he died. However, maybe it was not so much that they wrote it down, as it was the Beloved One who preserved the story for the community.
I am open to many of these possibilities, but while speculation certainly produces interesting conversation, I prefer the anonymity of the Beloved One. In their earliest forms, the Gospels, particularly the passion narratives, may have first had a performative and liturgical function in the community. Perhaps, under these circumstances, early Christians and baptismal candidates listened to John's passion narrative on the eve of Easter and were invited to imagine themselves as the Beloved One, resting their head on Jesus, present at the Cross, asked to take in Jesus' mother as their own. Maybe, in this regard, John's Gospel also invites us to imagine ourselves as the Disciple that Jesus loved.