It helps in identifying how a site structures its dynamic content. The Risks of Predictable URLs
When you search for , you are asking Google: "Find all public web pages where the URL contains the variable 'pk', the variable 'id', and the number '1' immediately following them." inurl pk id 1
?id=1 AND 1=1 (normal response) ?id=1 AND 1=2 (different or empty response) It helps in identifying how a site structures