Measuring ROI for different marketing channels can provide a clearer picture of where your efforts are paying off. SEO and PPC (Pay-Per-Click) campaigns, for example, require different approaches to ROI calculation. For SEO, the focus is on organic traffic growth and keyword rankings, while PPC looks at the cost per click, impressions, and conversions. Social media marketing ROI is typically measured by engagement rates, follower growth, and click-throughs, while email marketing success is often determined by open rates and conversion rates. Each of these channels contributes to the overall digital marketing performance, and understanding their specific ROI helps fine-tune strategies for better results.