I rarely hear it emphasized among Christians I talk to but as I see it, I interpret Jesus as Lord in contrast to Caesar as Lord. A little context:
When Paul said Jesus is Lord, there was beginning to happen in Rome in the first century, the worship of Caesar as Son of God, Lord and Savior. The Caesar was considered the divine Savior because he brought peace to Rome through violence and for example bringing back slaves to Rome after conquering other peoples; who were basically treated as sex slaves.
So when Paul proclaimed "Jesus was Lord," he was presenting a new moral ideal in seeing Jesus as the ideal Emperor rather than Ceasar. His rhetoric was also an insurgence. There was even the gospel of Ceasar, the good news of through Caesars killing other people and dominating them we now have, for example, people we can treat as property and use as sex slaves. Paul was countering this with his gospel or good news, that Jesus as Lord does not kill, bully and exploit people; but came to set people free and He demonstrated for imitation a new Way (the path of Radical Hospitality, Agape Love, and Healing, etc.). Christ as Lord inaugurated the better ideal, the Realm of God, manifesting Heaven's Realm into the world through his words and actions.
After Jesus died his disciples took up their calling as imitators of The Way and took to writing letters, Epistles and Gospels: that presented artistcally a non-violent emerging parabolic memeplex. Note that Sue Blackmore changed her mind and acknowledges that religion is not a mind virus, as she used to describe religious memes; and she now thinks religious memes can be healthy and beneficial memetic replicators. This ethical memeplex continued to organically spread Jesus' Way on earth (like seeds planted into soil and sprouting and flourishing) through the "called out ones" (Christians) who bodily imitated the Way of Christ and verbally spread the good news of Jesus as Lord (rather than Caesar as Lord).
