Although the “good design rule” says that a web page should not be too long, there are long web pages that require scrolling. Depending on the formatting of the web page, sometime there is a need to scroll horizontally in addition to vertical scrolling.
With very long web pages, a user may also want to search the page content for specific patterns. Most browsers provides a means to search for text patterns within a web page.
Most properly formatted web pages also make sure of links and headers within the same document. This helps a user locate a particular portion of the document quickly.