What Are Parameters? A Clear Guide to Meaning, Benefits, and How to Use Them
Phrases like "please add this parameter" or "make sure the UTM parameters are set" are part of the daily vocabulary of marketing and web teams. But the word "parameter" means different things in different contexts: it can refer to an identifier appended to a URL, a configuration value inside a program, or even a coefficient in a machine learning model. This article focuses on URL parameters, the kind most commonly used in marketing and web analytics, and walks through what parameters are, how UTM parameters and ad-platform-specific parameters relate to them, the benefits they offer for attribution and on-site behavior analysis, a five-step process for managing them correctly, and common pitfalls such as duplicate content and naming inconsistencies.
A parameter is a general term for a value that is passed from outside a system, program, or URL to influence its behavior or output. It is often translated as "variable," "argument," or "configuration value," and the precise meaning varies by context. In the marketing and web analytics world, "parameter" typically refers to a URL parameter (query parameter) appended to the end of a web page's URL.
A URL parameter takes the form ?key=value appended to a URL. For example, in https://example.com/page?utm_source=google&utm_medium=cpc, the URL contains two parameters: utm_source=google and utm_medium=cpc. Parameters pass information to servers and analytics tools and are used for a wide variety of purposes, including identifying the traffic source, preserving search conditions, tracking sessions, and switching content displays.
In a broader sense, "parameter" can also refer to targeting conditions configured inside Google Ads or Meta Ads campaigns, hyperparameters in machine learning models, or query parameters in API requests. This article focuses on URL parameters, which marketers and web managers encounter most often in practice.
There are several types of parameters used in marketing, each with its own purpose and usage pattern. Understanding the differences sharpens the accuracy of both your measurement design and your site architecture.
A URL parameter is a value appended to the end of a URL in the form key=value, preceded by ?. Also called query parameters or query strings, they are a general-purpose mechanism for sending information from a browser to a server or passing identification data to analytics tools. Multiple parameters are joined with &, as in ?key1=value1&key2=value2.
The use cases are broad: passing search keywords (?q=keyword), filtering and sorting product lists (?category=bag&sort=price), pagination (?page=2), A/B test assignment (?variant=b), and marketing measurement (?utm_source=...). You'll find URL parameters used across nearly every part of modern web development.
UTM parameters are a specific type of URL parameter designed to identify traffic sources in detail for analytics tools like Google Analytics. The name originates from "Urchin Tracking Module," a predecessor analytics tool acquired by Google, and UTM parameters have remained the de facto standard ever since.
There are five UTM parameters: utm_source (the origin site or media, e.g., google, newsletter), utm_medium (traffic channel, e.g., cpc, email, social), utm_campaign (campaign name, e.g., summer_sale_2026), utm_term (search ad keyword), and utm_content (ad variation identifier within the same campaign). The first three are treated as required, while the last two are optional in most conventions.
Each ad platform issues its own automatic tracking parameters. Representative examples include gclid (Google Ads), yclid (Yahoo! Ads), fbclid (Meta Ads), and msclkid (Microsoft Ads). These are automatically appended by the platform when a user clicks an ad and are used for downstream conversion measurement and integration with the ad platform itself. Whereas UTM parameters are "tracking parameters that humans design," gclid and its peers are "identifier parameters that platforms issue automatically".
URL parameters can also be classified into two broad types based on their behavior: passive parameters and active parameters. Passive parameters (measurement parameters) such as UTM parameters and gclid only pass information without changing the content of the page. Active parameters, on the other hand, such as sorting, filtering, and pagination, change the page content based on the parameter value. Understanding this distinction is especially important when designing parameter usage with SEO in mind (covered in detail later).
The growing importance of URL parameter usage is rooted in the diversification of digital advertising channels and the maturation of user-behavior-based optimization. With traffic coming from a mix of social ads, search ads, display ads, email, and external media placements, modern marketing requires a precise mechanism for measuring "which channel, which campaign, and which creative brought users who converted, and by how much."
The first benefit is accurate traffic-source visibility. By applying UTM and platform-specific parameters under a consistent rule set, you can track "source/medium," "campaign name," and "performance by creative" in detail within Google Analytics 4 (GA4) or your MA tool. Vague observations like "traffic from social is up" get replaced by precise statements like "the July campaign generated X conversions through the third carousel slide of our Instagram ads."
The second benefit is a deeper understanding of on-site behavior. When search queries, filter conditions, sort settings, and page numbers are captured in logs as URL parameters, you accumulate behavioral data showing exactly how users searched and compared. That data feeds directly into site improvements, e-commerce operations, and recommendation tuning, creating the foundation for both UX and CVR improvement.
The third benefit is flexibility when implementing personalization and A/B tests. URL parameters let you assign A/B test variants with ?variant=b, switch copy based on traffic source with ?ref=newsletter, auto-apply coupons with ?coupon=XXX, and reflect all of this in site-side logic with ease. As a common language that ties together ad operations, MA, CRM, and site improvement, parameters play an essential role.
Below are concrete examples of parameters you'll commonly handle in day-to-day work, organized by category. You can also use this as a checklist for reviewing your own measurement setup.
As mentioned earlier, UTM parameters consist of five elements: utm_source, utm_medium, utm_campaign, utm_term, and utm_content. Standard practice is to use utm_source for the media name (google, facebook, newsletter, etc.), utm_medium for the channel type (cpc, email, social, display, etc.), and utm_campaign for the initiative name (e.g., spring_campaign_2026). utm_term records the search-ad bidding keyword, and utm_content records creative variations within the same campaign (carousel_a, image_b, etc.).
Representative examples include gclid (Google Ads), gbraid/wbraid (newer Google Ads parameters for iOS), yclid (Yahoo! Ads), fbclid (Meta Ads), msclkid (Microsoft Ads), ttclid (TikTok Ads), and li_fat_id (LinkedIn Ads). These identifiers are automatically appended by the platform when an ad is clicked and are used for conversion measurement and detailed reporting within each ad platform.
Examples include ?q=search_term (search results pages), ?category=xxx (category filters), ?sort=price_asc (sorting), ?page=2 (pagination), and ?color=red&size=m (product attribute filtering). While these improve site usability, they also increase the number of unique URLs generated, which requires careful handling for SEO and measurement purposes.
Other parameters in common business use include identifiers for links inside newsletters, affiliate_id to indicate traffic from external partners, session_id for session continuity, debug for test environments, and cid (client ID) for internal use. When introducing custom parameters, make sure the names don't collide with other platforms or standard parameters.
Simply adding parameters isn't enough. Without proper design and operational rules, you'll see side effects ranging from reduced measurement accuracy to SEO problems. The following five-step workflow delivers both accurate measurement and a clean site architecture.
The first step is defining what you want to learn. Start with analysis goals like "compare CVR by channel," "calculate ROI per campaign," or "understand which newsletter links get clicked," and work backwards to determine what parameters you need. Adding UTMs without a goal in mind leaves you with reports that don't support decisions downstream.
The biggest stumbling block in parameter operations is naming inconsistency. If one person writes "facebook" for a Facebook ad while another uses "FB" or "fb_ads," GA4 treats them as separate channels and your aggregate numbers drift. Document a list of allowed utm_source values, enforce alphanumeric lowercase, choose a delimiter (underscore is recommended), avoid non-ASCII characters, and manage all of it in a single spreadsheet or tool.
Use Google's Campaign URL Builder or an equivalent URL generator to produce parameter-tagged URLs that follow your rules. Keep a history of issued URLs in an internal database or tool so you can trace "when, for which initiative, and which URL was used." If you use URL shorteners like Bitly, always verify that parameters are preserved correctly through the redirect.
Before launching, click through the tagged URLs in a test environment or your own browser and confirm that the parameters are captured and reflected correctly in GA4's DebugView, real-time report, or your MA tool's tracking view. Typos and case-sensitivity issues are extremely common sources of lost measurement, and thorough pre-launch testing dramatically improves the reliability of your results.
Once an initiative is live, review parameter-based reports regularly and compare results by media, campaign, and creative. When you find insights like "this combination has the highest CVR" or "this channel contributes most to LTV," feed them back into budget allocation, creative direction, and offer design to keep the improvement cycle running. At the same time, review your naming rules and URL-issuance process periodically to keep parameter operations healthy across the team.
Parameters are a powerful tool, but misuse can compromise measurement reliability and SEO. Keep the following typical failure patterns in mind.
The first is naming inconsistency. When "google," "Google," and "GOOGLE" coexist in utm_source, GA4 counts them as separate channels and your totals skew during analysis. Either normalize the variations at the table level or enforce consistent input at the source.
The second is appending UTM parameters to internal links on your own site. When internal links are tagged with UTMs, GA4 ends the user's current session and starts a new one, overwriting the original traffic-source information. UTMs should only be used on links that drive users from external media to your site, never on internal links.
The third is duplicate content caused by parameters. When active parameters like ?sort=price and ?page=2 generate too many URL variations, search engines may see multiple URLs with identical content and spread SEO value across them. Countermeasures include setting canonical tags to designate the preferred URL, properly managing insignificant parameters in Search Console, and optimizing crawl efficiency through robots.txt and internal linking.
The fourth is appending personally identifiable information (PII) to parameters. Putting email addresses, phone numbers, or names into URL parameters creates a real risk of leaking that data through browser history, server logs, or referrer headers. GA4's terms of service explicitly forbid sending PII. If identifiers are needed, use values that can't be tied back to an individual, such as hashed IDs.
The fifth is parameter overload. Stuffing ten or twenty parameters into a single URL creates real-world problems: URLs that can't be shared on certain social platforms, links that get cut off in emails, and a higher chance of tripping spam filters. Include only the parameters you truly need.
A parameter is a value passed from outside a URL or system to influence its behavior. In marketing, parameters most commonly take the form of URL parameters such as UTM parameters and ad-platform-specific parameters. They are foundational to data-driven marketing, powering accurate traffic-source visibility, on-site behavior analysis, personalization, and A/B testing.
The key to success is faithfully executing a five-step process: clarifying measurement goals, enforcing naming governance, managing URL generation and distribution, verifying measurement, and iterating through analysis. Avoid common traps like inconsistent naming, internal UTM tagging, duplicate content, and PII leakage, and keep your setup simple and consistent. Done well, parameters become a foundational piece of infrastructure that dramatically improves the performance of your marketing, ad operations, and site analytics.
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