All the court cases for that particular day are wiped from the records books and it is like it never happened.
But here is the tricky part, the court will try to fool you and get you back into the system by sending notices. Whatever you do, don't open any mail sent to you by the court. If you do, you will be obligated to answer the charges.*
Remember, don't open those notices! Score dude, you just got out if it completely free and clear.
-KeithP
*I am not an attorney or legal authority. Follow my advice at your own risk.