Scannability and Readability in Web Writing

Reading online is 25% slower than reading from printed material, and it's harder on the eyes.

Web users scan for information rather than reading content word-by-word, so we need to break down the text. Use short headings, lists, and short paragraphs to make content more scannable.

Headings

Use headings and sub-headings to organise the page into sections and help readers find specific topics and information:

Include key words from the associated paragraphs.
Keep headings and sub-headings short, a maximum of 4-8 words.

Lists

Lists draw the eye, so break down important information into concise list items.

Check long sentences. If there are a lot of commas, colons, and/or semi-colons, try pulling the points out into a list.

Keep the text for each list item short - a 5-line list item isn't a bullet point, it's a paragraph with a bullet in front of it.

Have no more than 9 items in a single list.
Keep lists to a maximum of two levels.
Use numbered lists where the order of entries is important.
Use bullet point lists where the sequence of entries isn't important.
Ensure each list is introduced by at least one line of text.

Paragraphs

Short paragraphs keep content scannable. Many readers will scan only the first sentence of each paragraph - perhaps the first two sentences if they're very short.

Get to the point straight away, in the first line.
Build each paragraph around a single idea.
Paragraphs should be no longer than 40 - 70 words.
Paragraphs should be no more than 5 lines.
Keep summary paragraphs to 30 - 50 words.
Try to vary the size of paragraphs.

Bold Text

Use bold text sparingly.

Using bold text for emphasis on the Web is a cheap trick. It looks unprofessional.
Don't use bold words inside prose text. Keep bold for headings and - if you absolutely have to use it - restrict bold text to the lead-in at the beginning of a paragraph.
If you have to bold text to emphasise words inside a paragraph, the paragraph is probably too long. Try breaking it into two paragraphs (or more).
Remember - making everything bold, effectively renders none of it bold.

There's an exception to these rules when highlighting important information. Even then, restrict bold to Note: or Important! and leave the message itself un-bolded.

Block Lettering

Don't shout.

Only use all capital letters if you want to SCREAM at the reader - otherwise, keep it down to a conversational level by restricting capitals to their proper places.

Structuring Web Content Counting Words for Web Writing