No, we will not be talking about the physical marker here that has been used to highlight a page or docment one is reading or has read. We are talking about markers punctuations, words, phrases and other useful things to make your post/article reader friendly. Please note this is not part of a style manual just some random notes and points picked up through the years.
The Bible begins with In the Beginning. Some Fairy Tale begin with Once Upon a Time and ends with And They Lived Happily Ever After. There are words and phrases in any language that can be used to: (i) Point out things; (ii) To compare; (iii) Begin and end; (iv) and a a number of other things
A period or a full stop tells the reader when a sentence stop. A punctuation can also tell the reader when a set of words pauses and then continues. It can also tell the reader when things get exciting or quiet.
When you enumerate or list things.Bullets if all items on the list are of equal importance. And numbered if there is a sort of ranking. Then again its a matter of style and what is important is that a list focuses the readers attention to a set of fact, information or knowledge.
It can also be used to signal that should be taken when one wants to achieve something. In this instance a numbered list is more effective because it means that it is a step-by-step process.
Sometimes things are best said from the source. A quote is a powerful tool. It adds credibility to the story. A quote can build up your story: A quote from President Barak Obama carries more weight than a Chef at a five star restaurant, unless of course the topic is about restaurants.
The format of the word or phrases in an essay, article and even post can if one wants to bring out the word or phrase within the essay. Standing out has its advantages. A term that needs to be defined can be formated to stand out. It could be the name of an author, title of the book, name of a place, and many other things you would want to get notice.
Content is king but presentation is Queen. An article or post has to have some value added feature that will help further explain or make interestomg. And sound, image and moving images can do that.