Can you believe a woman got fired from her job for using all caps in an email? There’s something about all caps text that turns people off. Using it in a social context means you’re yelling. But using it on your website means bad readability for your users.
Many websites use text in all caps to emphasize their message. However, what they’re actually doing is de-emphasizing their message because text in all caps reduces the shape contrast for each word.
The shape of any word in all caps for any type of font, sans-serif or serif, is a rectangle. This means that text in all caps show a parallel edge at the top and bottom of a word, giving it low shape contrast. But text in title style capitalization show multiple adjacent edges at the top and bottom, giving the words high shape contrast.
The more nonparallel edges your text has, the higher the shape contrast it has. High shape contrast makes words easier for users to recognize. If you want to make your text easier to read, consider using title style capitalization instead of all caps on your website.
When is it okay to use all caps? All caps are fine in contexts that don’t involve much reading, such as logos, headings, acronyms, and abbreviations. But when your message involves reading, don’t force users to read words with bad shape contrast. The caps lock key is a key that designers should rarely use.
In emails, using all caps is a sign of bad manners. In design, using all caps is a sign of bad readability. Know when and when not to use all caps, and you’ll have a better chance of keeping your users and your job.