While the rules of netiquette are constantly evolving, unchanged norms include frowning upon off-topic posting, trolling and spamming. Other common norms include avoiding the use of all caps and reply all.
Those who post in online discussion threads particularly frown upon off-topic posting as this practice distracts other users from the original subject of the discussion. Trolling, the practice of posting inflammatory messages with the intent of provoking other users, is also against the rules of netiquette, especially if it is framed as a personal attack. Spamming, the act of posting advertisements for products usually unrelated to the topic being discussed, is another practice the rules of netiquette prohibit.
Other than distracting methods, netiquette also specifies rules concerning the tone for individuals to use when communicating online. Writing using all capital letters is usually unwelcome in online communities due to the perception of anger that comes with this practice. In general, netiquette specifies communicating in a manner similar to that of a face-to-face exchange.
Certain rules of netiquette apply specifically to email communication. Users frown upon employment of the "reply all" function for a message concerning a personal matter or an inconsequential news item. Also, netiquette highlights the need for proper spelling and concise paragraphs.