utmsource

utm_source is a parameter used in the Urchin Tracking Module (UTM) tagging system to identify the origin of website traffic. It is part of a set of campaign tags employed by analytics platforms to attribute visits to specific sources, such as search engines, newsletters, or other referring sites. The canonical parameter name is utm_source; some reports or nonstandard implementations may display variations like utmsource, but utm_source is the standard form.

In practice, utm_source accompanies other UTM parameters such as utm_medium and utm_campaign, and optionally utm_term and utm_content. When included in a campaign URL, it provides a human‑readable source label that allows analysts to distinguish traffic from different origins. For example, a URL might include utm_source=google alongside utm_medium=cpc and utm_campaign=spring_sale. The value should be a concise, consistent label, with lowercase names being a common convention to avoid duplicates.

Best practices include using stable, descriptive source names that remain consistent across campaigns (e.g., google, newsletter, facebook), avoiding spaces or special characters by using hyphens or underscores, and tagging all campaign links uniformly. This consistency supports reliable cross‑campaign comparisons and reporting in analytics tools. If multiple sources drive traffic, utm_source enables channel‑level segmentation and performance analysis.

Limitations include reliance on users clicking tagged links; traffic from untagged links or cross‑domain navigation may be attributed as direct or unknown. While utm_source is widely supported across analytics platforms, correct implementation and consistent naming are essential for accurate attribution.