I finally re-found this page written by a Mr. Jim Lesurf, a retired reader of Physics and Electronics at the School of Physics and Astronomy at St. Andrews University. I read it several years ago but than I forgot where to find it.
In summary, Mr. Lesurf points out that "digital" and "analog" are just concepts and that a signal exhibits properties of both.
http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/iandm/part12/page1.html
Of particular interest is his take on the "digital defects" of the LP format.
http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/iandm/part12/page2.html