Started my online business six months ago and was confused why my sales numbers never matched my advertising reports. Facebook would show 15 conversions but I actually had 28 sales that day from people who clicked my ads. Couldn't figure out what was wrong until I learned people switch between devices constantly during their buying process. Someone sees my ad on Instagram while on their phone then buys on their laptop at work the next day and my tracking loses them completely. Found this helpful guide RedTrack on cross-device tracking that explains why most attribution fails and how to fix it. Now my marketing budget goes to campaigns that actually work instead of ones that just look good in reports