I usually wouldn't post in a thread with this many answers already, but it seems every answer you have gotten is a little bit off target.
It means that you do not dispute the charges against you. The symbolic meaning is that you are not admitting guilt, but accepting the punishment.
As for the current case, it has the same effect as pleading guilty, as in you will be convicted and sentenced. The only practical benefit is that it cannot be used automatically against you if you end up being sued civilly for example.
Let's say you are in a car accident, and the prosecutor charges you with reckless driving, if you plead guilty and the victim sues you for compensation, you have already admitted the facts of the case. If you pleaded no contest, they would have to argue for a jury and convince that you were in fact responsible.
In most jurisdictions and for most cases, you will not be allowed to plead no contest.
(The actual legal term is nolo contendere)