Writing for the Web.
Coming at the web from the perspective of a writer, it can be easy to despair. You might be used to writing for all sorts of media: newspapers, magazines, books, or even radio, film or television. The web, though, is different enough to what's come before that it demands you sit up, pay attention, and adjust your writing style if you want your writing to work on the web.
Subheadings are Key.
Do you see what I'm doing here? I gave you a short introduction, and then I go straight into a series of subheadings. These subheadings divide the article up into clear sections, letting you dart around, scan more easily, read the bits you're interested in, perhaps go back and read some you didn't think you were interested in... it's really up to you. Web readers simply cannot abide being given a big chunk of text and having to sort through it themselves – they want clear sections in your writing. Note that your subheadings should be much more descriptive and less 'creative' than they would be in print.
Make Sensible Paragraphs.
When it comes to the web, paragraph splits are, surprisingly enough, less necessary than they are in print. You will make your site look odd if you put in a paragraph break after every sentence, or every two sentences. Instead, split paragraphs when you start a new idea – note that if you combine two, many readers won't register the second. In most cases, you shouldn't go for too many paragraphs before introducing a new subheading. Your aim at all times is to make your page as easy as possible for a reader to scan.
Lists are Always Good.
If you're about to write out a big list with commas and semicolons, stop. Semicolons have no place on the web. Instead, you should be using lists, complete with bullet points, to get your point across effectively. Treat it less as prose and more as a presentation. Clear presentation of information lets people find what they're looking for more quickly.
Of course, you shouldn't go overboard with the lists. If you have more than one list in a row, or your list goes on for more than ten items or so, you might want to consider revising the layout of your writing.
Don't Be Afraid to Link.
It might feel strange at first, but link whenever you're talking about something that isn't included in an article. You're quoting a dictionary or encyclopaedia definition of something? Link to it. Are you reviewing a website? For goodness' sake, link to it! There is absolutely no justification for fear of linking: it's the way the web works, and if you're not linking when you could, you're not writing for the web.
Make Everything Independent.
On the web, you can't be sure that your text is always going to be seen together. Maybe your headline will be listed in an index of headlines. Perhaps your intro will be next to it. You just can't be sure. In every case, then, you have to resist the temptation for mystery, and play things straight. Imagine how your headline and intro would look if they were detached from the rest of the article. Would you know what the article was going to be about? Would you click through to read it?
You should pay particular attention to this problem if you're used to writing short, punchy headlines and explaining yourself in sub-headlines: realise that the sub-headlines might not always be there, and adjust your style accordingly.
Listen to the Authority.
This has really just been a brief introduction to the kinds of things you should consider when you're writing for the web: there's plenty more out there. If you want to read the best articles on the subject, though, you should read Jakob Nielsen's articles on writing for the web, at http://www.useit.com/papers/webwriting/. Although many of them explain the results from research that was done quite a few years ago now, they remain as relevant today as they were when they were written. Spend an hour or two making notes, and watch your writing improve.