When the Bible says " do not take the Lord's name in vain" I sway towards the meaning being more to do with saying you are a child of God (a Christian) when you are not. It is taking His name upon yourself.
As a Christian I am uncomfortable with societies use of God's name, particularly the name of Jesus Christ being used as a swear term.
I'm also grateful we don't live under Old Testament laws as one section of Leviticus tells of a young man who used the name of God as a swear word and tells of God's jealousy over His name.
"Now an Israelite woman's son, whose father was an Egyptian, went out among the people of Israel. And the Israelite woman's son and a man of Israel fought in the camp, and the Israelite woman's son blasphemed the Name, and cursed. Then they brought him to Moses. His mother's name was Shelomith, the daughter of Dibri, of the tribe of Dan. And they put him in custody, till the will of the LORD should be clear to them. Then the LORD spoke to Moses, saying, “Bring out of the camp the one who cursed, and let all who heard him lay their hands on his head, and let all the congregation stone him. And speak to the people of Israel, saying, Whoever curses his God shall bear his sin. Whoever blasphemes the name of the LORD shall surely be put to death. All the congregation shall stone him. The sojourner as well as the native, when he blasphemes the Name, shall be put to death."
