Comma long sentences for clarity; however, this usage is regarded as an error in modern times. The comma and the quotation mark pairing can be used in several ways. In American English, the comma is commonly included inside a quotation mark: In Great Britain and many other parts of the world, punctuation is usually placed within quotation marks only if it is part of what is being quoted or referred to: There is also some difference regarding the use of the serial comma, which is an optional comma placed before the coordinating conjunction in a list of three or more items:
Punctuation of English in text messaging and other short-form online communication, where more formal or "closed" punctuation can be misinterpreted as aloofness or even hostility. Open punctuation eliminates the need for a period at the end of a stand-alone statement, in an abbreviation or acronym (including personal initials and post-nominal letters, and time-of-day abbreviations), as well as in components of postal addresses. This style also eschews optional commas in sentences, including the serial comma. Open punctuation also frequently drops apostrophes. Open punctuation is used primarily in certain forms of business writing, such as letterhead and envelope addressing, some business letters, and résumés and