Marketing reports & analytics: Reports the referrer for each individual page, excluding values that match internal URL filters. Marketing reports & analytics also optimizes traffic source data. It reports only the top 20,000 unique referrers per day in each report suite. All other referrers are removed from reporting. This optimization helps ensure that the Referrers report returns quickly in the interface.
Data warehouse: Reports only the first referrer of the visit, regardless of internal URL filters. The data warehouse capability also includes all referrers regardless of the number of unique URLs.
Data warehouse containing more data or domains than marketing reports & analytics: The following are potential reasons why this comparison can happen.
- Internal domains/referrers: Data warehouse does not respect internal URL filters. If the first page of a visit contains a referrer internal to your site, it is recorded in data warehouse but not marketing reports & analytics. A common example would be when a user browses to your site, and lets their visit expire (30 minutes of inactivity). Then, the user clicks a link to start a new visit.
- Edge-case domains/referrers: Marketing reports & analytics only reports the top 20,000 referrers. Data warehouse however includes all referrers and domains, regardless of the number of unique values.
Marketing reports & analytics containing more data or domains than data warehouse: Because marketing reports & analytics looks at all page views, not just the first page of a visit, mid-visit referrers are seen in marketing reports & analytics but not data warehouse.