Generations ago, ships' masters knew that someone fresh from land was little help at first. A full-rigged vessel had a seemingly insoluble tangle of ropes with which to set sail and it took time and help to learn how to handle them. It took a lot of experience in all types of weather to know how to handle the ropes. The expression expanded from there to any experienced person in any area of activity.
I asked a rabbi who gave me the following answer. He says he's pretty sure this is where it came from: "Keikl" (pronounced KY-kle) is yiddish word meaning "circle." Jewish immigrants would sign their papers at Ellis Island with a Keikl or a Keikleh (a "little circle"), since they were unwilling to make an "X." Once they started working as storekeepers or peddlers, they continued to use keikls instead of X's to sign account books and other documents. So Jews became known to Ellis Island immigration inspectors, and others throughout the country as "keikl men" or "kikes."
Like so many other things we use today, ketchup was believed to have invented by the Chinese, who called the condiment "ke-tsiap." The Dutch, who were heavy importers of the item in the 18th century, spelled it "ketjap." It evolved into the spelling we used today.
Meaning: Maintaining an appearance of affluence and wealth for the benefit of others.
Example: In this world people don't respect you for accumulating wealth, they respect you for spending it. Most people who seem rich have very little wealth, they spend it all keeping up with the Jones's.
Origin: Jones is an extremely common surname in the United States and in this phrase is meant to be a generic term for the neighbors. The phrase makes much more sense when you say "keeping up with the neighbors".
It is a common practice in suburbia for neighbors to be fiercely competitive, and to continually try to have the nicest house, lawn etc. in the neighborhood.
"Keeping Up With the Joneses" was the name of a comic strip that ran across the United States from 1913 to 1931. Arthur Momand based it on his experiences as a newly married young man making $125 week and living in New York. He originally wanted to name the strip "Keeping Up With the Smiths," but changed it to the Joneses because it seemed "more euphonious."