I'm sure everyone is familiar with the verse:

Matthew 12:2 - "Judge not, that ye be not judged.  For with what judgment ye judge, ye shall be judged: and with what measure ye mete, it shall be measured to you again."

There are all sorts of interpretations going around about this verse.  Most of them can't hold up once a closer look at them is taken.  Just about everyone I have asked says, "Well, that verse says you're not supposed to judge."  That's wrong...Let's continue reading the verses and pick up on the rest:

Matthew 12:2-5 continued from verse 3 - "And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?  Or how wilt thou say to thy brother, Let me pull out the mote out of thine eye, and behold, a beam is in thine own eye?  Thou hypocrite, first cast out the beam out of thine own eye; and then shalt thou see clearly to cast the mote out of thy brother's eye."

So, in reality, this verse is aimed directly at hypocrites telling others their wrong-doings.  If a kid and his friend has a huge problem with pornography, one of them has to first conquer that sin in his life before you he help his friend out, assuming they are trying to save the friend from the sin and they aren't combating it together as brothers in Christ, leaning on each other's strength.

Now that we know who this verse is directed at, we can aim responses to the people who say "You're a Christian!  You aren't supposed to judge!"  For one, the bible didn't say not to judge.  It said not to judge other people and their sins when one's own eyes are blinded by sin.

Below is a verse that states directly that Christians will judge others.  But, that isn't all it says, keep reading:

2 Corinthians 2:15 - "But he that is spiritual judgeth all things, yet he himself is judged of no man."

It is directly stated that a man who is Godly and spiritual will judge things.  He is supposed to be judging according to the standard God set down through the Bible, His Word.  If we continue to read this verse we will understand that God says we will be judging by His standard and not our own.

2 Corinthians 2:16 - "For who hath known the mind of the Lord, that he may instruct him?  But we have the mind of Christ."

We have the mind of Christ and will be using it to judge others with.  What we see as morally right and morally wrong is to be what the Bible says is such.  God's laws are to be upheld and we Christians are the only ones who are able to tell others what is truly and morally right and wrong.

God says certain things are sinful, for example cussing is a sin (2 Timothy 2:16).  If I go up to a person and tell them that cussing is wrong, they'll possibly tell me "Don't judge me!  Judging is wrong!"  When, in reality, the only thing I'm doing is telling them what God said.  I didn't judge them, the judgment had already been made.

As a Christian, we are asked to try and help other people out of their sinful ways and win them to Christ.  If a brother falls into sin, we are to try and help him back to the gospel, but in a humble manner (Galatians 6:1 - Read it here)  By not telling others when they are wrong we are doing a disservice to the Lord Jesus Christ.  Don't be afraid of how others will react.  It isn't us they are rejecting, but Christ.