The agreement is useful to The Guardian to set the rules and guidelines for visitors, users and customers:
Registration: inform users that they must agree to a set of rules when they register on your website or mobile app
Disable or terminate accounts: inform users that their accounts can be disabled or terminated if abuses happen on your website or mobile app, e.g. spamming, swearing etc.
Owner of content: notify users that you, the company, is the owner of the content appearing on your website or mobile app – except in cases where other users can post content (upload, share, create etc.) where the users are the owners of such content
Changes to the agreement: users should be informed about upcoming changes to the agreement before the changes are applied.
DMCA: The Guardian is also informing owners of copyright content that they can submit a DMCA notice to the website if they found infringing content in their DMCA clause.
These are only a few examples of what kind of clauses and disclosures you can add in this kind of agreement.