Tag Management and Data Collection
Rules, data elements, and the publish pipeline
Adobe Experience Platform Tags are the recommended collection layer. Understand the object model: a property contains extensions, data elements, rules, and environments. Data elements are named getters (CSS selector, JS variable, cookie, local storage, custom code) and should be the only place selectors live. A rule is event plus conditions plus actions, with an execution order, a run-sequentially option, and per-action timeouts. Libraries are built and published through Development → Staging → Production, each environment with its own embed code. A saved change is not live until the library is built and published to the production environment, which is a favorite exam trap.
Know both tracking libraries. AppMeasurement sends page views with s.t() and link or synthetic hits with s.tl(linkObject, 'd' or 'e' or 'o', linkName). Link tracking transmits only the variables listed in linkTrackVars and linkTrackEvents. Web SDK (alloy.js) sends a single sendEvent call with an xdm object, uses a datastream and the Edge Network, and requires Analytics variable mapping in the datastream configuration. The tracking server concept becomes the edge domain.
Other traps: assuming a saved rule is deployed; confusing Direct Call rules (triggered by _satellite.track) with custom events; writing custom code where a data element belongs; reading a data element in one rule before another rule sets it; and forgetting that turning off the Analytics extension library management setting means the extension injects AppMeasurement for you.
Rule of thumb: anything used twice becomes a data element, and anything a marketer might change becomes an extension setting rather than hard-coded JavaScript.
Worked example: an outbound partner link rule uses a click event with a condition that the link href contains /partner/, then actions that set eVar5 from a data element and send a beacon as s.tl with link type 'o' and a link name, and with eVar5 listed in linkTrackVars so it actually travels.