If most of your customers use iOS, you almost certainly have a marketing data problem. Apple devices throttle the ability to measure multiple sessions for the same user - as a result, you're rarely able to see any attribution data beyond the last click that drove the sale. All assisting channels, campaigns and visits can't be 'stitched' to the session and user that actually drove the sale. That's a massive problem. Let's look at a specific example: - You begin researching mattresses (Google searches, LLM chats, reading buyers' guides etc) - You see a post or ad on Instagram for a new mattress - you click the link and browse through their site. All good. - A week later you see an ad on YouTube; same brand - you click the link and head to their site - 2 weeks later, you're new bed frame is on its way from another retailer and will be delivered tomorrow. You search for 'Emma mattress', click their branded Google Ad and complete your purchase with next day delivery. In this example, iOS only lets you see the 'last click' channel in your analytics platform and Google Ads would take 100% credit for that sale. The data is telling you a very short-sighted story but the truth is, if you never saw that relevant ad on Instagram whilst researching, or didn't see that YT ad at the right time, you likely wouldn't have completed that purchase at all. Why does this happen for iOS users? This is thanks to technology called Apple ITP. It's great for your privacy (as an iPhone/Apple customer) but it's frankly a serious pain in the arse for marketing teams. Here's how it works... After 7 days of inactivity on a website, iOS silently deletes all marketing cookies - or any cookies that were set by JavaScript. It gets even worse... If the cookie was set from an ad click (contains fbclid, gclid, msclkid etc) then cookies are silently deleted by iOS after just 24 hours. So any clicks from ads to your website cannot be attributed to a user's previous sessions if they were more than 24 hours ago - which in many cases, is likely be be 90%+ of your ecom customers. Customers rarely buy anything within 24 hours of visiting your website for the first time, and they're even less likely to purchase during their first session. The problem gets worse as the 'consideration window' increases. So for example: - Buying a new t-shirt as a first-time customer from a household name (low) - Buying weight loss injections from an online pharmacy (high) - Buying a new TV (high) - Purchasing a new skincare routine from a new brand (high) The moral of my story here is this: For all ecommerce brands I work with, I address this data problem first. Instead of losing visibility of users 24hrs after they click ads, I'm able to keep that user, sessions, assisted channels and their purchases aligned for up to 400 days. This is why server-side tracking in non-negotiable if you're in ecommerce (particularly Shopify).