The structure of electronic messages can take two primary forms: one utilizing unformatted text, the other employing a markup language for richer presentation. The former presents content as a sequence of characters without styling or embedded elements. A typical example would be a simple message consisting solely of letters, numbers, and punctuation. The latter allows for the incorporation of elements such as images, varied fonts, and styled layouts.
The choice between these two structures impacts message size, rendering consistency across different platforms, and security considerations. Historically, simpler formatting was preferred for its universal compatibility and reduced risk of malicious code. More sophisticated formatting offers greater design flexibility, enhancing user engagement, but necessitates careful attention to rendering discrepancies and potential security vulnerabilities.