In addition to signing a document to ensure that it cannot be altered without detection, you may apply a 'time-stamp' to ensure that it cannot be backdated or postdated. For example, changing the exact moment at which a contract is signed may favor one party at the expense of another party. Creating a time-stamp for the document would fix the exact time beyond doubt.
To time-stamp a document, you must subscribe to a Trusted Third Party and configure EEcerts to use its URL, either directly or from a profile. The TTL deals with the Time Stamp Authority (which actually generates the time-stamp) for you. The TTL will supply you with the new signing certificate and time-stamp: you just need to store these with the document.
You can also configure the time-stamp to include your TTL user name and password such that it can only be decrypted on that computer; it would render a stolen EEcerts database unusable.