Book publicity is one of several related and sometimes confusing or nearly synonymous “p” terms.
Someone does promotion (which often includes public relations) to achieve publicity. They all can be part of an author's platform.
Publicity is lots of people knowing about your book and hopefully buying copies and/or urging others to buy.
Promotion is all of the efforts intended to achieve publicity. Although publicity is the end result of promotion, many people call themselves book publicists and relatively few call themselves book promoters. (Publicists used to be called "press agents"). A publicist or promoter can guarantee to provide promotion, or public relations, but cannot guarantee that you or your book will achieve publicity.
Red Hot Internet Publicity is mis-titled. Author Penny C. Sansevieri uses "publicity" as a synonym for "marketing," and it wasn't until I reached page 115 of her 193 pages that I encountered anything that I considered to be related to the book's title -- which was the reason I bought the book.
The bulk of the book's beginning deals with setting up a website. Penny gives both inaccurate information and bad advice. She says that a typical website should cost between $2,000 and $6,000 to build. That number is bullshit and may unnecessarily scare off writers who could benefit from having a website. Nice websites can be built inexpensively -- or for free.
Penny also recommends hiring both a designer and a coder to put the website together. More scary bullshit.
I am not a professional designer or a coder, but I have put together well over 50 websites that worked just fine. I've done them for myself, for my businesses, for other businesses, and for friends.
Amazon indicates that Penny's book has been updated. I hope it's been fixed.
Despite its name, public relations is not directly concerned with relations with the public. Media are intermediaries. Writers hope to attract the attention of media people by sending out press releases, or by contacting journalists, editors, bloggers, talk show hosts, TV producers and movie makers.
Promotion includes more than public relations. It may include public appearances, publicity stunts and platform building.
Platform is a major buzzword in current publishing. It’s not the same as a political party’s platform. Think of it as a metaphor for a structure that will boost you up and make you visible to potential readers, sources of publicity and bookstore buyers. Components in your platform include websites, blogs, business connections, social media, radio and TV appearances, quotes in media, online mentions, speeches, articles, friends, neighbors, etc. Your first book is part of your platform and should help sell your later books.