This template is used to generate a link to a certain section of an article that has an appropriate section mark (§).

Instead of:

[[History of IBM#1969: Antitrust, the Unbundling of software and services|History of IBM § 1969: Antitrust, the Unbundling of software and services]]

...you can write:

{{Section link|History of IBM|1969: Antitrust, the Unbundling of software and services}}

which is much shorter and does not require you to search for section mark.

Both generate:

History of IBM § 1969: Antitrust, the Unbundling of software and services