URL Parameter

A URL parameter is the part added after a question mark in an address (like ?utm_source=telegram) to carry extra information such as a filter, an ID or a campaign tag.

A URL parameter has two faces. Its useful face is that it carries a signal: UTM parameters that tag source and campaign, or parameters that set a list's filter and pagination. Its troublesome face is that these same parameters split one page into several different addresses in the report; if a parameter has no analytic value (like a session ID or a random parameter), it only clutters the pages report and should be stripped in normalization. There is a security and privacy rule too, often violated: personal or sensitive data (a phone number, email, token) must never be put in a URL parameter, because the address persists in the server log, browser history and the referrer header and leaks. So a good parameter is one that either carries an analytic signal or reflects the page's state, not one that carries the user's identity.