A fork of Rural Dictionary
The current date visible in a photo, e.g. written on a peice of paper or personin photo's skin, in order to prove the photo is genuine. Often used on /b/ when people post pics of themselves.
OP: Hey look at my huge titties Anonymous: Timestamp!!!
A period of time when the truth is told by a friend
Mike told Kenny his girlfriend is a bitch at about 12 o'clock midnight. Wow, he Timestamped his ass!