Publishing terms cause much confusion, for new and seasoned authors alike. Most of this confusion comes into play when an author uses his or her opinion as part of the definition of a service. If an author disagrees with a publishing method, he or she may say it is a scam. However, writers of all levels use all forms of publishing depending on their needs.
Vanity publishing is perhaps the most misunderstood form of publishing. The term 'vanity' comes from the belief that anyone who uses this type of publishing must be so vain that they just want to see their name on the cover of a book. In reality, vanity publishing is more of a mindset than an actual service. Vanity is in the eye of the beholder, and there are several good reasons why you should choose a vanity publisher.
With vanity publishing, you as the author will pay to have your book published. Since you are footing the bill, you should not have to get your book approved by the publisher as you would in a traditional setting where the publisher is taking a financial risk on your ability to write successfully. You may or may not be offered editing and formatting services, and these may come with your fee or might be at an additional cost. Basically you are paying a printer to print your books, with the possibility of a few extra perks.
If you are interested in publishing a book for personal use, need editing services, and don't want to spend a lot of time with the formatting and presentation details, vanity publishing, or pay-to-print, could be a viable option for you. This is no different than designing a brochure or manual for company use and having it printed. There are some things you just want to see bound neatly, such as your family history, favorite recipes, or collection of your kids' poems and artwork.
Vanity publishing has pros and cons just like any other publishing service. The reason many professional writers shun this method is because for their line of work, there are better options. Vanity publishing, or pay-to-print, is definitely not a recommended publishing method for authors who are making a concerted effort to make money as a career writer, build a reputation as an author, and mass-distribute their works. For those needs there are better options, but pay-to-print publishing still has its place in the world.