Firstly, the web is not homogeneous; there are three main areas to consider:

Emails: These are relatively informal communications between friends and professional colleagues. Obviously you can write whatever you want in a personal email, and use whatever style you want. However, we're so used to chatty emails that it's easy to forget that communicating with an editor or colleague is actually business correspondence: even email needs to convey a professional impression. There will be time enough for informality when you have established a rapport. Typos and emoticons may not matter in an email to a friend. Used in the wrong place in a business email, they may lose you a sale.

Mailing lists & special-interest groups: Unless copied and redistributed, articles published on limited-circulation lists will only be read by registered users. The information is often only of temporary relevance and therefore inappropriate for a print publication with a long lead time. In general, you can assume that most subscribers to the list share your interests, so relative informality is fine. The main thing to aim for is to be brief and informative or entertaining. Not everyone will share your exact viewpoint, though, so you should be wary of offending people unintentionally.

Websites, web pages, blogs & on-line forums: Most of these texts are available to the general public and will be archived semi-permanently. Although you have a lot of control over what you publish (and "unpublish") on your blog, and you can cancel your own messages on the Google groups, for example, once information has appeared anywhere on-line, however briefly, it is likely to have been copied and saved away somewhere. If something written in the heat of the moment isn't to come back and haunt you in the future, there are two golden rules:- One: never be malicious. Two: post only what is true and accurate.

As well as all the standard off-line considerations of readers' interests, logical construction, coherence, proof-reading etc., when it comes to web-writing style, there are certain guidelines to bear in mind.

In general, readers don't usually spend as long reading on-line as they do reading printed publications. You might leave a magazine open half-way through an article and pick it up again at your next coffee break. But once an on-line reader moves on, he probably won't come back. So the writer needs to get the message across as quickly as possible. If you summarise the most important information at the beginning, the reader can see immediately if he's in the right place; if he is, he'll read on to where you expand your ideas.

Reading from the screen tends to be slower. Combining this with the limited time spent reading, a good rule of thumb is to keep your word count to about half what you would for print.

It is much easier for the reader if on-screen sentences are short and written in simple language and if each (short) paragraph deals with a single idea.

People scan web pages rather than reading sequentially. Sub-headings, lists and bold texts are useful as they help readers find the information they are looking for. Do be careful, though, not to make your texts too "busy". In the same way that long texts are off-putting, pages with lots of different type-faces and links look difficult and most readers just won't bother.

Web writing tends to use a more informal style than print. But remember that the readership is international: if you use puns and "clever" humour, they may misunderstand. Or they may be offended. This explains the popularity of emoticons: they are an attempt to clarify subtleties of tone which may not be understood by the reader in a hurry. Of course, emoticons aren't always appropriate, so you need to craft your writing to avoid potential ambiguity.

It's worth taking that extra time to make sure your on-line writing is as clear, accessible and easy to read as possible. After all, there's a world-wide readership out there who could be reading what you write.