We had this question as a Facebook competition question. It was fun, but we got too many wrong answers which is a little bit disconcerting.  There are different dates you have to be aware of as a notary. Some are more important than others, and each date has its own function.
 
Signature Dates
The date the signer signs the document is the signature date of the particular signature.  There are cases when a husband and wife will sign the same document, but on different dates.  People are busy, and two notaries could handle the same paperwork on two separate days with two separate signers.  Those split signings are tricky, and are more likely to have to be redrawn.  But, just as long as you get paid, don’t stress!
 
Notarization Dates
The date you notarize someone’s signature is the notarization date.  The date corresponds to the signature, not the document.  A document could be signed by more than one party on different dates.  Or an addendum could be added and signed on another date as well.  Its complicated.
 
Document Dates
This is the question that 90% of the notaries got wrong.  I had very few choices of contestants to put in the drawing to win Starbucks!  The document date is NOT necessarily the date the document was drawn up, although it usually is.  It generally should not be dated after the signing to avoid confusion.  It is often dated the day the signing is intended to happen on, and is often dated the day it was drawn, or sometime in between.  There is no rule governing when the document date can be.  The function of this date is to be an identifying mark on the document to distinguish it from other documents.  Of course, if you have ten documents all entitled, “Affidavit“, to be signed by the same two parties, and all having the same document date, it really doesn’t narrow it down.
 
Your Journal
If you live in a state that doesn’t require journals, please don’t read this paragraph.  Actually, do read it, and get a journal anyway.  Your journal of official notarial acts is your record of all notary acts that you have done in your commission. It is evidence if you ever have to go to court, or if you are ever questioned about a particular act. It adds to the integrity of the notarization and safeguards against fraud, especially when you take thumbprints for all documents (optional, but recommended).   If a fraudulent notarization takes place with someone impostering you, without your journal, you will never have proof that you didn’t notarize that person. Journals keep records in sequential order, so you can go back to July 3rd, 2003, and see that you indeed never notarized Shelly Deeds and her Deed.
 
Backdating
In your career, you will most likely eventually be asked to put a fraudulent date on your notarial certificate which is refered to as backdating. This is illegal, and you can lose your commission as a result, if you get caught.  A lender might need you to date the certificate for the 27th, when its the 28th, so that the borrowers can keep their lock. Its their problem, don’t get involved.  Lose the client and keep out of jail! Please see our blog article entitled “Backdating from A to Z”

You might also like:

A lady lost a great account because she wouldn’t backdate!
http://blog.123notary.com/?p=22229

Leave a few spaces open in your journal

The transaction date = the signature date: Feb 2013 Phoninar
http://blog.123notary.com/?p=4054

How do I fill out a journal entry?
http://blog.123notary.com/?p=1725