Capitalization

[Tina]

Capitalization is the difference between I had to help my [uncle Jack] off a [horse].. and I had to help my [uncle jack] off a horse..

[Michiko]

The action of writing or printing in capital letters or with an initial capital.

[Dave Paprocki]

One of the most commonly misused aspects of basic grammar.
Usually taught in the first year of education, a capital letter is used at the start of a sentence, and for names and [titles]/headings. This includes the names of people, organizations, places, days and months, and (often forgotten) the name of a language, brand or ethnicity. There are a few other examples, which a quick Google search will explain. It is considered acceptable to use block capitals instead of [italics] to emphasize a specific word or point. It is retarded to use capitals for every word, or just your favorite words, or [sporadically] throughout a text.