Nicked from McDowell’s comment on the same page, and indirectly from the Unicode docs:
Traditionally, NLF started out as a line separator (and sometimes record separator). It is still used as a line separator in simple text editors such as program editors. As platforms and programs started to handle word processing with automatic line-wrap, these characters were reinterpreted to stand for paragraph separators. For example, even such simple programs as the Windows Notepad program and the Mac SimpleText program interpret their platform’s NLF as a paragraph separator, not a line separator.
NLF (New Line Function) in this context is shorthand for CR, LF and CRLF. By contrast, the two Unicode characters have unambiguous uses.