Accented characters, shapes, arrows and uncommon punctuation
We are familiar with some of the special ‘character entites’ available in html, such as & (for an &), however, there are a great many of them around. Most can be refered to by name or by number. For example, the prime (or feet) symbol (′) can be written as either ′ or ′. It is generally better to use the number reference, as the numbers are reconised by more user agents (and most of the names aren’t in the xml standard). Other entities include ↵ (↵), ≠ (≠) and é (é).
Within the entities there lies a great number of punctuation marks that are now uncommonly used. In an A List Apart article several of these are discussed.