The General Data Protection Regulation (GDPR), which took effect on May 25, 2018, is a set of regulations governing the use of personal data across the EU. This is forcing some affiliates to obtain user data through opt-in consent (updated privacy policies and cookie notices), even if they are not located in the European Union. This new regulation should also remind you to follow FTC guidelines and clearly disclose that you receive affiliate commissions from your recommendations.
Affiliate marketing is commonly confused with referral marketing, as both forms of marketing use third parties to drive sales to the retailer. The two forms of marketing are differentiated, however, in how they drive sales, where affiliate marketing relies purely on financial motivations, while referral marketing relies more on trust and personal relationships.