Churches representing the past - Revelation 2:1 - 3:6
Church at Ephesus represents the apostolic period from A.D. 30 - 95, when the Church was concerned about organization and doctrine to the point that it became legalistic.
Church at Smyrna represents the persecuted church which existed from A.D. 95-312. It was the Church that existed at the time the Book of Revelation was written.
Church at Pergamum represents the apostate church that existed from A.D. 312 to 590. This period developed after the Emperor Constantine was converted, and the Church and the state were welded together. As is always the case in such unions, the state began to corrupt the Church.
Church at Thyatira represents the dark ages, a pagan period from A.D. 590 - 1517, when the papacy developed, and the Church became full of Babylonian occultic practices.
Church at Sardis represents the dead church (from A.D. 1517 - 1750) which had a reputation for being alive, but was more a reformation of the old, rather than a literal resurrection of the first century Church.
Churches representing the present - Revelation 3:7 - 3:22
Church at Philadelphia, the "alive Church," represents a period of Church History from A.D. 1750 until the present, and is known as the Church with a focus on missions to the world. It is also known as the faithful "remnant" which will experience the Rapture of all born again believers.
Church at Laodicea, the visible Church of today, is a church in name only, and due to its worldliness, apathy, and apostasy, it is the church that will not even let Jesus in. Unless they repent, and allow Jesus Christ His rightful place in their their "country club," they will be left behind after the Rapture, and will face the seven-year Tribulation which follows.
It really does not matter how one interprets this passage!
What does matter is what one believes about Jesus!
Are you living your life with Jesus at the center of it?
Or, is Jesus still waiting for you to invite Him in?