BBC wrote:
Flaming and trolling are two linked terms that refer to types of behaviour on the Internet, and most notably derive from Usenet and BBS (bulletin board systems) systems. This type of behaviour is still fairly common in IRC (Internet Relay Chat) and at sites such as Slashdot.org.
Flaming
The term 'flaming' is defined slightly differently depending on which site you're on, but generally it means the same thing wherever you go. h2g2 defines it thus:
Flaming means posting something that's angry and mean-spirited - the online equivalent of flying off the handle.
... whereas, according to the Jargon Dictionary, the term 'flaming' originates at MIT1 from the phrase 'flaming a.....e'. The definition of 'flame' on this site goes on to define flaming in the following four ways:
To post an email message intended to insult and provoke.
To speak incessantly and/or rabidly on some relatively uninteresting subject or with a patently ridiculous attitude.
Either of senses 1 or 2, directed with hostility at a particular person or people.
(n) An instance of flaming. When a discussion degenerates into useless controversy, one might tell the participants 'Now you're just flaming' or 'Stop all that flamage!' to try to get them to cool down (so to speak).
Interestingly, the Jargon Dictionary also goes on to speculate:
It is possible that the hackish sense of 'flame' is much older than that. The poet Chaucer was also what passed for a wizard hacker in his time; he wrote a treatise on the astrolabe, the most advanced computing device of the day. In Chaucer's Troilus and Cressida, Cressida laments her inability to grasp the proof of a particular mathematical theorem; her uncle Pandarus then observes that it's called 'the fleminge of wrecches'. This phrase seems to have been intended in context as 'that which puts the wretches to flight' but was probably just as ambiguous in Middle English as 'the flaming of wretches' would be today. One suspects that Chaucer would feel right at home on Usenet.
Trolling
For many years, Usenet was the dominant form of online communication. It defined 'trolling' in three ways:
... a posting designed to attract predictable responses or 'flames'; or, the post itself. Derives from the phrase 'trolling for newbies' which in turn comes from mainstream 'trolling', a style of fishing in which one trails bait through a likely spot hoping for a bite. The well-constructed troll is a post that induces lots of newbies and flamers to make themselves look even more clueless than they already do, while subtly conveying to the more savvy and experienced that it is in fact a deliberate troll. If you don't fall for the joke, you get to be in on it.
... an individual who chronically trolls in sense 1; regularly posts specious arguments, flames or personal attacks to a newsgroup, discussion list, or in email for no other purpose than to annoy someone or disrupt a discussion. Trolls are recognisable by the fact that the have no real interest in learning about the topic at hand - they simply want to utter flame-bait. Like the ugly creatures they are named after, they exhibit no redeeming characteristics, and as such, they are recognized as a lower form of life on the net, as in, 'Oh, ignore him, he's just a troll.'
... [Berkeley] Computer lab monitor. A popular campus job for C[omputer] S[tudies] students. Duties include helping newbies and ensuring that lab policies are followed. Probably so-called because it involves lurking in dark, cave-like corners.
Trolling is generally recognised as being an occupation rather than an occurrence, ie while people can (and do) flame for the sake of flaming, flaming can often simply be a manifestation of someone's overreaction to something someone else said. It is for this reason that while flaming is, almost without exception, frowned upon, trolling is more looked upon with scorn than its erstwhile counterpart. The website Slashdot.org, mentioned above, even goes so far as to have a method of forum moderation which allows postings to be classified as 'troll' (as well as such other labels as 'interesting', 'funny', and 'irrelevant'). Users who troll in situations like this generally troll for bait, as mentioned in the definition above.
Reasons for Flaming/Trolling
The troll has but one purpose, to inflame the people who read it and draw them into an argument, and as such is a deliberate attempt to provoke. Aside from sheer immaturity, there are many reasons for the flame, such as:
Ranting
Most people feel the need to have a good rant or vent at someone, usually after frustration at lack of service, an unsatisfactory experience or just general bad mood. It is not unheard of for pupils to anonymously flame their teachers. Most people feel the need to have a good rant at some point, but usually restrict their outburst to friends, family or even a diary.
Complaint
Unsatisfactory service, poor customer care, lack of information, or late delivery of a product can all result in a flame to the company. Most are simply complaints with 'colourful metaphors', but some are plainly abusive, and many companies operate a zero tolerance on this, even in emails, and will ignore/delete the message.
It should be noted that abusive comments do not make companies want to deal with them any faster. Customer advisors will sometimes deliberately 'misdirect' the customer's comments to the wrong department, although most reputable companies do deal with complaints correctly. On the contrary, a polite, professional, and pointed phone manner works wonders with first-level agents (the staff who initially ask phonecalls), and their supervisors. It isn't unheard of for a canny customer to have him/herself escalated to second-level employees (who are generally better equipped to handle queries) by a supervisor, or even the third level (in IT, generally the staff who designed the product or have something to do with the development team).
Insult
Many flames are just insulting emails or messages. Usually the person sending the flame had little reason for flaming, it may even be as trivial as a long delay for an answer they need.
The insult can be a joke between friends, such as:
Hey donkey brains! Fancy a pint tonight?
But even this can get out of hand. As the recipient has no emotional clues to go by (tone of voice, slight smile, etc), the flame can be misinterpreted as a genuine insult. Emoticons or 'Smileys' can help (a smiley face to denote humour or a 'winkeye' smiley -

- to denote irony or playful malevolence both work wonders). However, these are not foolproof - many people dislike the use of emoticons as they are sometimes used to mask genuinely unpleasant comments with pretences of friendliness.
Challenge
Few pleasures in life are greater than a lively, cordial debate and a troll can often get one going. More scathing trolls, however, are likely to provoke a so-called domain (or site) war. These have a tendency to get seriously out-of-hand and drag everyone in, as sooner or later everyone has an online friend who has been insulted, flamed and/or trolled.
Generally, a flame or troll is an unpleasant (intentional or not - though usually intentional) message which lambastes the recipient.
Accident
The worst flame of all. This is one that the sender never meant to direct at the recipient. It is usually either an email sent to a friend that is accidentally sent to the wrong person (or every person, using the 'Send All' or 'Reply All' button accidentally) or is passed on from the recipient to someone else.
Offices are the usual location of this faux pas. Usually someone complains about their boss to a friend via email, but accidentally sends it to the whole office, or the friend passes it on until it reaches the boss. It demonstrates the dangers of email, as many people send off a message while still angry, without thinking. The best advice on this is; never send anything via email that you wouldn't shout across a crowded room.
How To Deal With A Flame or Troll
Choosing how to deal with a flame can be a difficult choice. The wrong one can lead to further flames, insults and even exclusion.
Ignore It
Usually the best method, but not always appropriate for flames. Public (newsgroup/forum) flaming needs some sort of response, even if it's just a friendly request to tone the language down. Moderators will normally do this, either through regular monitoring, or through a reporting service.
Ignoring a troll is almost always the best policy. Since no-one rises to the bait, the troller will get bored and go away. Users in newsgroups and forums frequented by trolls often swiftly append to any such thread (or in reply to a baiting message) a warning like: 'Do not feed the troll'. Some online communities have measures in place to deal with offensive and ill-spirited content, such as Userfriendly.org, which deletes inappropriate messages. Other sites have moderation or complaints buttons in place in order to deal with inappropriate content, whereas, as mentioned previously, the technology news site Slashdot.org has a system in place for randomly-nominated users to rate messages, either through votes out of five or by character - including 'troll'. The default forum view in slashdot.org excludes messages with ratings beneath a certain level (ie, messages that have received a handful of 'moderator points' from randomly-nominated moderators).
Respond Rationally
Also quite a good method, and one that has the advantage of making the flamer look irrational and testy, is to respond to any baiting calmly and rationally. However a troll can be a direct challenge to your authority. They are difficult to ignore, although a reference to an earlier posting that answers all or most of the troll's points can be a good defuser.
Flame Back
A bad idea generally is to return fire. It never accomplishes anything except to leave a lasting record of your own suitability for trolling and a general bad atmosphere on the forum2. Flaming back almost always only serves to provoke the flamer, as most people love a good argument.
Explanation
It is always useful if you can remain calm, although this is not easy in all situations. Reply to the flamer, indicating that the flamer has misunderstood what you were saying, and offering a re-explanation of your comments. Particularly on forums, it has the advantage of making the flamer look irrational, that they have 'flown off the handle' without checking facts first. This also works quite well with trolls.