When they are synonymous with named or called, there is no substantive difference between entitled and titled. Some people object to this use entitled, but the objection is baseless. The use of entitled to mean named goes back centuries, and entitled was in fact the preferred term until recently. Google Books uncovers only 23 instances of the phrase “book titled” in works published in the 19th century, against some 31,000 instances of “book entitled.” (Titled in those days was much more often used to mean having a noble title.) This ngram, which graphs occurrence of the two phrases in English-language texts published from 1800 to 2000, shows that “book titled” did not gain significant ground until the second half of the 20th century:
The trend in this century goes against tradition. Google News searches covering the last few years show that titled now prevails by an approximately three-to-one margin. This is probably due to the growing use of entitled to mean having a right or claim to something.
Here are a few examples, spanning the last two centuries, of entitled used to mean named:
Mr Miller of Lincoln’s Inn has just published a book, entitled, “An Inquiry into the Present State of the Civil Law of England.” [Blackwood's Magazine (1825)]
A clever article entitled “Why Progress is in Leaps” might better have been entitled “A Review of the World’s Scientific Progress. [Michigan Law Journal (1896)]
Both the foregoing series by Hiroshige and Hiroshige II have been copied, practically line for line, by Hasegawa Sadanobu in a quarter-plate set entitled Shokoku Meisho Hyak’kei. [A Guide to Japanese Prints and their Subject Matter, Basil Stewart (1922)]
So certain were the Brazilians of victory that they had already written and recorded a victory samba entitled “Brazil the Victora.” [The Guardian (1950)]
The Rev. Donald Cozzens, author of a new and challenging book entitled ”The Changing Face of the Priesthood” will be the featured speaker. [Boston Globe (2002)]
Most examples of the use of titled from before the last few decades are like these (re-create our Google Books search here):
The titled Aristocracy being the choosers, we may in practice reject the two last Classes of Eligibles, as they would scarcely ever be resorted to. [Pamphlets for the People (1835)]
With such triumphs of aerial architecture did Mrs Nickleby occupy the whole evening after her accidental introduction to Ralph’s titled friends. [The Life and Times of Nicholas Nickleby, Charles Dickens (1839)]
Returning with her to the principal room, where a titled lady sat ensconced in the corner of a sofa, he rudely pushed her aside with the words: “Get out of the way, fat cow.” [Art and Life (1918)]
Titled here means bearing a noble title.
In current news publications, however, titled is very often used in place of entitled—for example:
Six years ago, The Times’ editorial board wrote a piece titled “The Math of the Market,” which argued that there was something special about having at least four companies competing in every segment. [Los Angeles Times]
The talent hunt, titled Scene Stealers, asked amateur film-makers to borrow from Film 4 productions over the years. [Guardian]
In a new e-book, titled How to Survive in a Recession, Mr. Thug (née Stayve Jerome Thomas) doles out forthright financial advice. [Globe and Mail]
Titled Ecce Homo (Behold the Man), the original was painted in oil in 1910 directly onto a column in the Iglesia del Santuario de Misericordia church in Borja, northeastern Spain.[News.com.au]
Examples of entitled used to mean named are still out there, but they are buried under thousands of instances of entitled used in its other sense.