In Word 2007 and Word 2010, the spaces between paragraphs were taller than the spaces between each line within a paragraph. This looks more familiar to a web-native user as browsers usually handle text in a very similar way.
In some cases, however, a user might want to switch back to regular spacing because of a necessary style or preference.
Changing paragraph spacing in Word
Select the text with the paragraph spacing you want to change, or select the entire document with Control + A. Under the Home tab, click on Change Styles in the Styles group and choose Paragraph Spacing.
Hover over each style to preview the change. No Paragraph Space was the default in Word 2003.