Why is there a -30- at the end of some newspaper articles?

The -30- at the end of an article signifies to the editor that he or she has reached the end of the copy, or writing.

There are many theories as to why the number 30 is used. One of the most popular theories is originates during the Civil War. When the first news was sent by telegraph to a press association, it was 30 Words long. The writer ended the message with -30- to indicate the number of Words. (Back then, editors needed to know Word counts or even inch measurements of articles so they could fit them onto the page manually.)

Another theory suggests that in the early days of journalism, xx was used to signal the end of a paragraph and xxx was used to signify the end of an article. xxx is 30 in Roman numerals.

However it started, -30- remains a tradition even in the digital journalism world of today.