Telegraphing involved a sender, a receiver and a cable between them. Contrary to sending a letter, the only way for someone to intercept a message was to go through the quite impossible process of cutting the transmission cord and setting an electric telegraph on the spot. For this reason, telegraphy became an important tool for in the political scene, in the military and also in business, such as communication with clients and for banking transactions.
Sending and receiving a telegraph is not like the simple task of typing letters and clicking on a button to send an email. Specialized professionals are imperative to sustain a telegraphy network and for this reason, during the heyday of telegraphic communication in the 19th and early 20th century, a high number of jobs were available to skilled professionals. On the contrary, you don't need professionals to send or receive an email or a phone call nowadays.
Telegraphy is a very slow communication method by 21st century standards. The first transatlantic telegram for example, sent by Queen Victoria to President Buchanan in 1858 , took nearly 18 hours to transmit. During the following decades the speed increased, but even the most efficient telegraphy networks cannot rival the speed of an email. No matter the location of the sender and the receiver, the message always arrives in full -- text and addenda -- within a matter of seconds.
Telegraphs are an efficient way to send information quickly, but they lack personal touch. The focus of telegraphs is on important information, as the speed of sending them depends on their size. However, modern communication allows senders to express themselves anyway they like. A long email, with complicated structure, long sentences and rich vocabulary takes only seconds to transmit; hence, you don't have to sacrifice speed for "personality" and vice versa.