Users prefer rows and columns on page to be aligned and, as a result, are better able to read the text. Reduce the amount of unused space on pages used for scanning and searching. On pages that are primarily links or categories, like a home page, the greater the density, the faster the scanning.
Density has no impact on user accuracy or preference.
As a rule, use less white space than you would on paper. Experienced users usually scan a Web page menu or a list from top to bottom. Users generally look at the top center of a page first, then look left, then right, and finally begin systematically moving down the total page. All critical content and navigation options should be at the top of the page. Particularly on navigation pages, all major choices should be visible without scrolling.