Yes, names do have power. Many Native American tribes had everyday names and "real" names that were not for daily use, to protect the bearer of the name from evil power. They might also have childhood names that were later changed to adult names based on something they had done or some event.

I once knew a Hindu-like group who felt that whenever you said God's name, you were calling on Him for attention. They considered this a good thing.

If the Jews do not use G*d's name because it is too sacred (it is often written like that to avoid actually using it), then perhaps the Christians, whose religion came from Judaism, are only taking His/Her nickname in vain? I think no one knows the true name of God, but he'll probably answer to most anything if you need Him.