ANAND - Even though it is hard to imagine, seeing his impressive record of false prophecy, that Joseph Smith was a prophet; let's for the sake of argument asssume that he was. Even if he was, the Bible warns us about people like him. Read Deuteronomy 13. If he talks about more than the God we all knew about before, and teaches us to act differently because of it, I consider that to be serving the other gods. Why do you follow those teachings which God has specifically warned against?

JOEL - I only follow the teachings of God and Jesus Christ that I have learned from both the scriptures and from modern day prophets.
In Deuteronomy 13, God was talking specifically to the Israelites whom He "brought out of Egypt". (Deut 13:5) If you remember, these are the same people who after being left alone for only a short while constructed and worship a golden calf. This was a warning to these people to beware of those who would take them away from God as it happened before. Joseph Smith's mission was to bring people closer to God.
If you use these scriptures to prove your point, then what about all the the additional things the people learned about God and Jesus in all the other books of the Bible that come after Deuteronomy? Are all those prophets and apostles wrong?
Jesus himself said, "For as Jonas was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth(Mathew 12:40)." However, Jesus was only dead for three days and two nights. Does that make him a false prophet?
"For the sake of argument" lets assume that Joseph Smith is a prophet and that he actually saw and talked to God the Father and Jesus. If that is true, then anything that God told him is probably going to be more current and more accurate and binding on us than anything that was written in the Bible thousands of years ago. The Bible is true as far as it is translated correctly. It helps to have a prophet to help explain those things that were not translated correctly.