Source tracking pertains to the ability of some hypertext

Hypertext

Hypertext is text displayed on a computer or other electronic device with references to other text that the reader can immediately access, usually by a mouse click or keypress sequence. Apart from running text, hypertext may contain tables, images and other presentational devices. Hypertext is the...

 systems to rigorously track the exact source of every document or partial document included in the system; that is, they remember who entered the information, when it was entered, when it was updated and by whom, and so on. This allows determining the exact history of every document (and even small parts of documents).

Present HTML

HTML

HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

 and HTTP do not have this feature, but certain systems on the World Wide Web

World Wide Web

The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...

 (such as WikiWiki

Wiki

A wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. Wikis are typically powered by wiki software and are often used collaboratively by multiple users. Examples include...

 and Everything Engine

Everything2

Everything2, Everything2, or E2 for short is a collaborative Web-based community consisting of a database of interlinked user-submitted written material. E2 is moderated for quality, but has no formal policy on subject matter...

) may have limited versions of the capability.