You have seen it used many times, but it often passes by without notice. It’s entirely possible that you had an English teacher who said it should never be done. You may have never contemplated using the second person perspective, the most direct and directed form. But you have seen it used all over the internet as one of the most immediate and direct ways of speaking to someone.
You can use it as an accusation or from inside someone’s head. Through its many uses and distinct flavors, you will find that nothing suits the internet quite like second person.
Because of its clumsy nature, you will find that second person is hard to maintain. You have only one subject, the pronoun “you” that has to be repeated constantly. You may be put off by the constant usage of this one word, but the effect is immediate and personal. You are having a conversation directly with the reader in the second person, speaking to them as if they are in the same room.
You will most often find this perspective used in instructions or other teaching situations. When you use the second person for teaching it is natural to become more passive and cautious. You may be speaking to the reader, but the subject matter still has to stand out. Use an implied pronoun to keep instructions from being repetitive, with the verb first and the subject simply left out in sentences such as “Insert the widget into the particle board table top with a big hammer”. Write each sentence as a continuation of the previous, tying together a paragraph as a complete thought and this form will begin to flow naturally.
Of all the uses on the internet, however, you run into second person most commonly as an accusation. You can see these examples on twitter and any other social media site when people are supposedly arguing politics but instead slip into a personal game that makes little sense at all. “You want to control people! You (fill in the blank) think the way you do because (fill in another blank)!” Ideally, you find this usage as boring as I do and will avoid it altogether.
Maintain the second person if you find it works to your benefit and allows you to speak directly to the reader. You may find that it becomes troublesome after a period of time, however. Give it up in a new paragraph, never changing in the middle. When you change perspective in the middle of a single thought you run the risk of seriously confusing your reader.
You can and should use the second person whenever a direct conversation with the reader is called for. But you must be careful how you use it and be very aware that you are writing in the second person. Watch for it and it will start to pop out to you in many places – but rarely maintained consistently and constructively.