So when should you start a new topic? Obviously, you’ll want to check what’s already been posted to make sure that your chosen subject hasn’t been raised before.

Having done that, if you find that you really have got something genuinely new to post about, then please start a new topic about it. Please don’t hijack an existing discussion and take it off-topic – including if it’s one you’ve started yourself! – as this only buries information and irritates other users.

Don’t forget to give your new topic a sensible subject title too.

If you’ve got a question or problem that other people might also have in the future, don’t be shy – post publicly, unless it’s a problem of a personal nature that would cause you or others genuine distress if it became public. That way, everyone can benefit from the shared knowledge and experience.

Writing an email entirely in one colour other than plain, sensible black is a bit like using stationery – it just suggests that you’re new to using email and are playing with the colours just because you’ve discovered they exist. So it’s bad for your image, especially in the office.

Some people think it’s clever to post on a forum in a different colour from everyone else because it will make their posts stand out more. Wrong. Writing entirely in bold red, blue or purple writing isn’t likely to impress anyone – it just marks the writer as an ignorant Yahoo who thinks that what they’ve got to say is more important than anyone else’s contribution. Besides, it’s self-defeating; if everyone else has the same idea then no-one’s posts are emphasised, so you end up with a psychedelic mess instead of a discussion.

Better to stick to black, unless there’s something exceptionally important in your posting that you particularly want to highlight. Important to others, that is, not to you. And even then, consider whether it’s so important that bold text alone isn’t enough to stress the point.

Let’s say the webmaster of Site A has a nice image on her site. The webmaster of Site B, casting around for eye candy to make his pages more attractive, sees the image and decides it would look good on Site B. Rather than asking Webmaster A or the original image copyright holder for permission to use the image, though, Webmaster B embeds the image into his page using Webmaster A’s server as his source.

Even if the image is subject to a free-use licence, using this kind of embedding means that every time the image is viewed, Webmaster A’s bandwidth is being used, not Webmaster B’s. This is theft, no matter how you look at it.

The same applies to forum postings; embedding a media file which is hosted on webspace that doesn’t belong to you is stealing bandwidth from the original host. Bandwidth costs money, and overuse can bring sites down.

Don’t embed files without permission.

That’s all very well for text messages, where the total number of characters was initially very limited. But there’s really no similar need in either emails or forum postings, as there’s usually no length limit. In any case, unless your readers are familiar with the set of abbreviations you’re using, they’re going to have to puzzle out the meaning – so any time you might have saved in typing your message is at their expense.

The same goes for l33t speak (“fear” becomes “ph34r”). This evolved as a coded language between gamers or hackers, and can actually take longer to type than straightforward English.

Unless you know that your reader is happy to use your particular jargon, type in plain English.

If it’s genuinely unclear to you where your chosen subject belongs, then either contact the Site Admins to ask them (if that possibility exists) or post it just once, in the board you think is most likely to be the correct one – and add a polite note to apologise in case you’ve got it wrong.

• Quote only the point or points you’re replying to;
• Quote a posting in its entirety only if it’s so short that to edit it would destroy the meaning;
• Quote from the directly preceding posting only if it’s a long one and you want to reply to a specific point or points (in which case, quote only those points).

If the immediately preceding posting is short, it will already be clear what you’re replying to. So quoting the immediately previous posting in its entirety serves no useful purpose and simply means that people reading the topic have to scroll through a lot of repeated material. Don’t do it. Ever.

On the other hand, don’t over-edit a quotation to the point where the original meaning is distorted; leave enough of the original words to keep the meaning clear, in fairness to the person whose words you’re quoting.

That’s great. But try to resist the urge to post on every topic on the forum you’ve joined, just because you can. If you don’t know anything about the subject in hand or the people already having the discussion, you’ll very quickly come to be regarded as a nuisance – and even if you do know something about it, you’ll be seen as a knowall and a busybody. Even worse, if you’ve included a link to your own website in your signature you may well arouse the site admins’ suspicions that they have a potential spammer on their hands.

So play it cool, at least until you’ve been around long enough for people to get to know you.

Of course, once something’s said, it’s impossible to unsay it. On a forum, it’s often different – you can go back and edit your post to remove something that you later realise was stupid or inflammatory or both. Sometimes (though not always) you can even delete your post altogether.

However, if you’re going to do this, please exercise a bit of consideration in how you do it. If you can edit it before anyone responds, that’s fine – with any luck you may have got away with it before anyone noticed.

But if people have already taken issue with your post, simply editing or deleted your post without comment is very bad form. It leaves them looking stupid, which won’t do anything to improve their moods.

Writing [Post edited] is better, but not much, as anyone coming along afterwards will still have no idea what the argument was all about.

It’s far better to give a brief summary of what you’ve removed and why. If you feel it’s appropriate, you could post a suitable expression of regret (or even an apology) after the latest post, but that will depend on the circumstances.

Better still, don’t edit or delete anything at all if it changes the meaning of what you’ve posted. If you regret what you said earlier, or want to correct a misunderstanding, post again and say so. Save edits for typos and spelling or grammar corrections.

Best of all, think more carefully about how others are likely to react to your post before hitting the “Submit” button in the first place.

(Some forum owners bar people from editing or deleting their own posts after a certain length of time has passed, or if the post has been replied to. This is a good thing.)

Ever been on a forum where a couple are sharing a username? Confusing, isn’t it?

You see a posting that looks interesting and respond to it, then think nothing more about it for the time being. Then a couple of weeks later you’re involved in a discussion with the same user (apparently) and make a reference to the previous postings – only for them to blankly deny all knowledge of the previous discussion. Only then does it emerge that two people are using the same identity to post, often at different times and each of them with no idea what the other’s posted. Disconcerting for other users, to say the least; and it can lead to all sorts of totally avoidable arguments.

It’s polite to other forum users to maintain your own username, no matter how loving your relationship with your other half. After all – c’mon, have you really merged so completely that you can’t maintain a distinct personality of your own?