Commas are often used in writing to increase the readability of text. They separate items in a list, clauses, phrases and much more. They are used before quotes as in, "Do you see the comma before those quotation marks?" They are also often utilized to mark parenthetical phrases within a sentence, for example, when interrupting a steady thought.
The comma is a very small punctuation mark. It somewhat resembles a period with a dash attached to the center right and then turned underneath into a hook shape. Despite its small size, it holds incredible importance. There is an old story of Czarina Maria Fyodorovna who once saved a man's life simply by misplacing a comma in a notice written by her husband Alexander III. The note was supposed to read "Pardon impossible, to be sent to Siberia." The man was set free after the Czarina misplaced the comma to read "Pardon, impossible to be sent to Siberia." His life was saved, simply due to a thoughtlessly misplaced mark of punctuation.
Commas are beneficial to both the reader and the writer of a text. With proper understanding of the comma's function, the reader can feel comfortable in the idea that they understand the meaning of a written text. The writer can implement proper comma use to properly communicate the idea he or she is trying to convey.
Commas are often confused with other punctuation marks because of its resemblance to other marks. For example, a semicolon features the first dot of a colon above a comma. The punctuation mark known as the apostrophe, which indicates possession and is used in contractions to represent omitted letters, looks exactly like a comma, only it is placed at the top of a letter, not at the bottom. There is also the misconception that commas can be used to divide ideas within a sentence, no matter how many ideas are placed in a sentence. This practice is known as "comma splicing" and it is not grammatically acceptable.
Perhaps the most popular type of comma (or at least the most popularly debated) is known as the "oxford" or "serial" comma. This is the comma used before the last item in a list of three or more items. For example, "I went to the store to buy milk, eggs, bread, and cheese." The comma before "and" is the hotly-debated oxford comma. It is debated among English language scholars because there is argument to its relevance or necessity with writing out lists.