Affiliate marketing generates significant UK e-commerce revenue. The affiliate earns commission for traffic or sales driven to the merchant. Disclosure of affiliate relationships is required by the ASA — "#ad" or "#sponsored" for any material relationship.

• ASA: affiliate links must be disclosed — material relationship rule applies
• Cookie duration: standard is 30 days — affiliate earns commission on purchases within that window
• PPC restrictions: commonly brands restrict affiliates from bidding on brand keywords
• Coupon/voucher affiliates: separate terms often apply
• HMRC: affiliate income is trading income — self-assessment required

Legal reference: ASA CAP Code; Consumer Protection from Unfair Trading Regulations 2008; ICO cookie guidance