Honestly, I never get it right when it comes to using these words. Most of the time I used dateline, and now I know it was wrong. But I believe most of us did not realize it either.
What is the difference between dateline and deadline?
Dateline is the day and time something happened, most often a news report, for example “Dateline Friday, June 26, 2015 at 10:00 a.m., the U.S. Supreme Court has announced that same-sex marriage is required by the Constitution.”
While deadline is the time by which a thing must be done, for example, “The Supreme Court’s deadline for issuing the opinion was June 30th, the last day of Court before the Justices went on vacation.”
So now you know the difference
But believe, I will not remember it in the next few days.