A small piece of code placed on your website that reports visitor behaviour back to an advertising platform, so it can measure conversions and build audiences.
A pixel is what lets an advertising platform know that the click it sold you turned into a sale. Without one you are flying blind: the platform cannot optimise towards buyers, because it never finds out who bought.
It is also what makes remarketing possible. The pixel records that somebody visited, and the platform can then show them advertising later.
This comes up most often in Analytics & Conversion Tracking. Analytics, conversion events, call tracking and reporting installed and verified, so every enquiry can be traced back to what produced it.
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