Thou shalt not take the name of the Lord thy God in vain...
We are commanded by the LORD to not use His name in vain in the third of the Ten Commandments.
We apply this one not as fully as we ought to in today's modern Christian culture.
Please give this some attention as it is a very important issue that involves the name of our Creator and King.
Thou shalt not take the name of the Lord thy God in vain; for the Lord will not hold him guiltless that taketh his name in vain. Exodus 20:7
In Exodus chapter 6 verse 3 God gives us His name. The focus here is not the translated name into the English language and whether it is correct or not but instead this is to point out that his name is not God.
In the preceding verse He stated "I am the Lord". There He is stating His position and not His name.
He gives His name in the following verse.
And God spake unto Moses, and said unto him, I am the Lord :  And I appeared unto Abraham, unto Isaac, and unto Jacob, by the name of God Almighty, but by my name Jehovah was I not known to them. Exodus 6:2-3
Relegating the concept of not using the name of the Lord in vain to just someone saying "God" flippantly is really over simplifying the command and actually it is using it out of context or more accurately not in its fullest context. This is especially true when folks fixate on that application alone.
God is not His name but it is a descriptive title of His role and He alone carries it with a capital 'G'.
More importantly, God's name is used in vain when people use it as a means to identify themselves as a "Christian" or a child of God's, and then live in such a way that shows they truly are not.
When people do things in His name but they do it for selfish motives or when they do things that are not according to His Word and then claim that they are doing those things for God, that is using His name in vain.
Using the name of Jesus flippantly is definitely using God's name in vain and yes, many do intentionally use "OMG" or "...God..." flippantly and when they do so they are indeed using His name in vain as well. Since many in the world today recognise that saying "God" in the context of cursing or cussing is blasphemy towards God in using His name in vain, then, yes, it is an unholy misrepresentation of His "Name".
In order to ensure that one is not using His Name in vain by misrepresenting Him, the true believer would meticulously and with much joy prove that everything they are doing is in line with God's character and void of any semblance of evil.
Prove all things; hold fast that which is good.  Abstain from all appearance of evil. 1 Thessalonians 5:21-22
A few more scriptures that speak about using God's name in vain. Take the time to read the last one from Malachi chapter one as it describes what today's churches do on a wide scale basis...
And ye shall not swear by my name falsely, neither shalt thou profane the name of thy God: I am the Lord. Ezekiel 39:7
So will I make my holy name known in the midst of my people Israel; and I will not let them pollute my holy name any more: and the heathen shall know that I am the Lord , the Holy One in Israel. Ezekiel 39:7
The burden of the word of the Lord to Israel by Malachi.  I have loved you, saith the Lord . Yet ye say, Wherein hast thou loved us? Was not Esau Jacob's brother? saith the Lord : yet I loved Jacob,  And I hated Esau, and laid his mountains and his heritage waste for the dragons of the wilderness.  Whereas Edom saith, We are impoverished, but we will return and build the desolate places; thus saith the Lord of hosts, They shall build, but I will throw down; and they shall call them, The border of wickedness, and, The people against whom the Lord hath indignation for ever.  And your eyes shall see, and ye shall say, The Lord will be magnified from the border of Israel.  A son honoureth his father, and a servant his master: if then I be a father, where is mine honour? and if I be a master, where is my fear? saith the Lord of hosts unto you, O priests, that despise my name. And ye say, Wherein have we despised thy name?  Ye offer polluted bread upon mine altar; and ye say, Wherein have we polluted thee? In that ye say, The table of the Lord is contemptible.  And if ye offer the blind for sacrifice, is it not evil? and if ye offer the lame and sick, is it not evil? offer it now unto thy governor; will he be pleased with thee, or accept thy person? saith the Lord of hosts.  And now, I pray you, beseech God that he will be gracious unto us: this hath been by your means: will he regard your persons? saith the Lord of hosts.  Who is there even among you that would shut the doors for nought ? neither do ye kindle fire on mine altar for nought. I have no pleasure in you, saith the Lord of hosts, neither will I accept an offering at your hand.  For from the rising of the sun even unto the going down of the same my name shall be great among the Gentiles; and in every place incense shall be offered unto my name, and a pure offering: for my name shall be great among the heathen, saith the Lord of hosts.  But ye have profaned it, in that ye say, The table of the Lord is polluted; and the fruit thereof, even his meat, is contemptible.  Ye said also, Behold, what a weariness is it ! and ye have snuffed at it, saith the Lord of hosts; and ye brought that which was torn, and the lame, and the sick; thus ye brought an offering: should I accept this of your hand? saith the Lord.  But cursed be the deceiver, which hath in his flock a male, and voweth, and sacrificeth unto the Lord a corrupt thing: for I am a great King, saith the Lord of hosts, and my name is dreadful among the heathen. Malachi 1:1-14
Another aspect of this is something that is very popular today. When we see those billboards, memes, etc that show quotes from God that are actually not recorded in the Bible we must realize that this is also taking His name in vain. Putting words in God's mouth is never a good idea especially when we know the consequences of adding to His Word.
Here is a prime example of this:
In closing, here is a clear example of using God’s name in vain. This demonstrates what can happen when someone tries to go around claiming to do things in the name of Jesus but they really do not know Him. His name is the only name by which men are saved (Acts 4:10-12) so using His name in vain can bring extreme consequences such as what happened to these men. This is in no way me saying that this will happen every time someone does this only that it has happened before to someone who really did not know Jesus and thus used His name in vain.
Then certain of the vagabond Jews, exorcists, took upon them to call over them which had evil spirits the name of the Lord Jesus, saying, We adjure you by Jesus whom Paul preacheth. And there were seven sons of one Sceva, a Jew, and chief of the priests, which did so. And the evil spirit answered and said, Jesus I know, and Paul I know; but who are ye? And the man in whom the evil spirit was leaped on them, and overcame them, and prevailed against them, so that they fled out of that house naked and wounded. Acts 19:13-16