Text is a very important part of user experience on the web, so it needs and deserves the same sort of design consideration. You must make your text usable in the same manner that you do the rest of your website or social media campaign materials. In short: text is user interface. Here are five rules for writing better for the web.
1. Know Your Objective
This actually applies to any sort of copywriting. Unless you have a clear picture of the end result, your writing won't be as clear as it could be. Ask yourself what you're trying to achieve with each bit of text you write. Once you know the objective, you'll be able to more clearly articulate what you need to get across to your customers in your copy, and you'll be able to identify any superfluous text that you can throw out.
2. Know Your Audience
The web is unique as a marketing platform because it can be so hyper-targeted. You can theoretically know exactly who your audience is and target your writing accordingly. Further, depending on where you're writing, your audience will be different. Any time your audience changes, you may need to make changes in your copy as well. Obviously writing for Twitter is different than writing for your blog, but writing for your blog is different than writing for email, which is different than writing for Facebook, which is different than writing for MySpace, and so on. Before you lay any words down on the page, figure out who you're speaking to, and write with them in mind.
3. Keep it Short
Studies have found that the more words you add to a web page the less time people spend reading it. Attention spans are shorter on the web, so your writing will be more effective if it is also kept shorter. One study found that users only spend about 4.4 seconds on a page for every 100 words of content. When you factor in average reading speeds, that means users generally only read about 18% of the text on a page (perhaps less -- since at least some portion of that 4.4 seconds is probably spent doing things other than reading page copy). That suggests that if you keep your copy as concise as possible, it will be more likely that your website visitors will actually read more of your text. Of course, you can adjust this rule based on your audience -- some audiences might be more likely to read long articles than others.
4. Make it Scannable
Because only a portion of your text is actually likely to be read by your audience, it's also important to write with scannability in mind. That means readers should be able to get the main gist of your copy even if they just scan it. When it comes to scannability, large blocks of text are your enemy. It is nearly impossible to quickly draw out the key points from a long paragraph, so when presented with one, many readers will just skip over it automatically. Make it easier for them to pull out the central topic points by using descriptive headers and sub-headers (like the ones in this article), bulleted lists, highlighting of key points, and images or diagrams, which can both break up the monotony of text and present the same information in a different way.
5. Embrace Constraints
Every platform has its own set of constraints when it comes to writing copy. The most obvious example right now is Twitter, which enforces a 140 character limit on every message you send, but every platform has limitations (for example, messages on Facebook can only have very limited formatting). These limits can be seen as a burden, or they can force you to think creatively about your content. If you only have 140 characters to work with, for example, you have to work extra hard to pack as much information as you can into each tweet while maintaining a voice consistent with your brand's other copy.