Posting to something on the internet for the first time in quite a few months or years. Usually n00bs do this, but sometimes a pro will do it to make people laugh.

This definition is a necropost.
Date: June 01, 1995
Comment: *long post about how computers will fit in your hand in 50 years*

Date: Feb 17, 2010
Comment: tl;dr
Sent from my iPhone

Date: December 31, 2011
Comment: Stupid necroposting Applen00b
Sent from Internet Explorer

Date: January 01, 2012
Comment: Stupid hypocritic necroposting Windowsn00b
Sent with my Ubuntu laptop

Date: March 10, 2098
Comment: I'm glad they banned proprietary software
Sent from my Debian smartglasses

Date: May 02, 2317
Comment: Look what I found in the archives! this is so funny loool
Sent from a Borg implant in my brain

Date: January 01, 10000
Comment: Hi, I'm the Doctor!
Sent from my TARDIS

Date: January 01, 1500
Comment: im a hacker
by Hex Luther May 30, 2015
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The act of posting in a forum thread that is too old to matter any more, or has served it's purpose.
Usually by new, inexperienced members of the board.

A common trait of someone necroposting is not to only bring one old thread back from the last page before deletion, but to fill up the entire first page with threads that only they seem to think have relevance to anything.
Date: 15th June 07
Comment: blah blah blah

Date: 2nd November 07
Comment: I totally agree!

Date: 2nd November 07
Comment: Quit necroposting.
by Fyrburn May 20, 2007
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to post in a thread that has been "dead", by being inactive for a relatively long period.
to post in a thread from 2002
by Eyeblood February 23, 2004
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A person posting in a really old topic. Such as a topic that is a year old. They look for old post and try to start them up again. Most necroposting is caused by the primitive race known as the n00b
TehSL1(01/3/04)Yeah Hl2 will be good
n00b(03/14/05)no way hl2 is teh suxorz
Kagami(03/14/05)stop nao necroposter!!
by Honto June 4, 2005
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In the context of the forums, the rootword of "necropost," which is "post," is most accurately defined as "a message published on a website." The prefix of the word, "necro-" most nearly means "dead." As such, the appropriate definition for a "necropost" (which can function as both a noun and a verb) would be "(v) the act of publishing a message on a website in a dead topic" or "(n) a message published on a website in a dead topic."
"dude... you just totally necroposted"
"lol what?"
"YOU POSTED IN A TOPIC FROM LIKE, 4 MONTHS AGO, LOLOLOLOL!"
by REP... rawr! November 28, 2007
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On a message board, posting something irrelevent on a really old topic to bring it to the top of the list topics. name comes from the fact that you are bringing it back from the dead, thus Necro. a practice common among n00blars.
n00b: I think necroposting is funny.
me: ::bitchslaps::
by Bob Dole January 17, 2004
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The act of posting something highly irrelevant to a forum thread that has not been posted to in months, even years, to bring it back from the dead.
9/23/2014:

I would have to say that TF2 is one of the best games ever made.

*insert 100 posts here, last one 9/24/2014*

9/23/2017:

lol

This is an example of necroposting
by SilverishGoldNova September 23, 2017
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