A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

Type to find tags:
Questions on the use, installation, and development of MaTeX--a package written by Szabolcs Horvát that makes it easy to use LaTeX-generated labels in Mathematica.
Questions on the use of spacing, signs, and typographical elements for the composition, parsing, and interpretation of expressions in Mathematica.
Questions regarding Mathematica cryptography related functionality (introduced in Mathematica 10).