Typesetting Paragraphs on Web Pages
I don’t know who started it, but at some point in the web’s relatively short history, we decided that paragraphs displayed on web pages should be “typeset” in a manner similar to what we see by default in a Microsoft Word document: an empty line after a paragraph, and no indent for each paragraph.
Somehow it was unanimously settled upon that the traditional manner of typesetting paragraphs — with indents and no spaces between paragraphs — is not as readable on a computer screen. In fact, the default styles applied by a browser on paragraph elements encourages the no-indent method. If you throw together an HTML document that doesn’t have any author styles defined, you’ll see the following when you inspect your paragraph elements in Chrome’s developer tools: