Stop shouting. TYPING IN ALL CAPS, espcially online, is considered shouting and is frowned on in most cases. In print, shouting is never worse than when it is done with decorative or script typefaces. It’s ugly. It’s hard to read. Just don’t do it, PLEASE!
That said, there are times when words set in all capital letters are necessary and acceptable. Just pay close attention to the fonts you use. Acronyms, such as NASA, and abbreviations such as PM or USA generally appear in either all caps or small caps within body text.
Note that acronyms and abbreviations within paragraphs are just a few letters set in all caps and are easy to read. Long headlines and especially paragraphs set with all caps are much more difficult to read and usually don't look as good as mixed case. Decorative fonts draw the eye and provide emphasis. All caps do the same thing. Combining the two techniques can overpower a page and overpower the reader.
- Avoid setting almost any Script typeface in all caps. Blackletter fonts don't usually do well in all caps either.
- Avoid using fonts with extreme serifs, swashes, or other decorative elements for all caps.
- Short headlines in all caps are better than long headlines in all caps.
- Fonts that are suitable for body text (serif or sans serif) are generally a better choice for all caps headlines than more decorative fonts.
- Nameplates and other text that serves as graphic embellishment can often be successfully set with all capitals that are slightly more decorative than typical body text.
- For an elegant and more readable look than all caps, set headlines or short phrases in small caps or specially drawn all caps Titling fonts designed to be readable in all capitals.
- Pay careful attention to kerning (space between letters) when setting any headlines, including those in all caps, to avoid unsightly gaps between pairs of letters.
The Bottom Line: Readability is the guiding factor when using all caps. Use all caps in moderation. Stick primarily with plain sans serif or basic serif typefaces or specially designed Small Caps and all caps Titling fonts for text in all capitals. Short headlines and other large type, such as newsletter nameplates, can take somewhat more decorative fonts in all caps. Save the unreadable all caps for certain logo designs or graphic text that is meant to grab attention by its appearance, not its actual text message.
"Right and wrong do not exist in graphic design. There is only effective and non-effective communication." — Peter Bilak - Illegibility