Clocks and track groups serve different purposes in PlayIt Live. The term "playlist" can be confusing as some people use it to mean track collections, others use it for scheduled content, or an hour's worth of programming - which is why PlayIt Live uses more specific terminology.

Clocks are hour-long templates that define the structure and timing of your broadcast content. They contain different types of items including track groups, fixed time markers, voice tracks, individual tracks, and break notes. When you schedule a clock to an hour, PlayIt Live generates the actual playout log based on the clock structure. For example, a clock might specify "play a track from the Songs track group, then a Station ID, then another song" - creating the framework for your hour.

Track groups are collections of tracks organised by type, genre, rotation category, or any criteria you choose. Examples include "A Rotation Songs", "Jingles", "News", or "80s Music". These track groups are then referenced within clocks to provide the actual content. When a clock item says "play from Songs track group", PlayIt Live will intelligently select a track from that group based on your scheduling strategy and playout policies.

The key difference is that clocks provide the structure and content flow for your broadcast hours, while track groups provide the organised pools of content that clocks draw from. You schedule clocks to specific hours via Clock Schedule, and the combination of scheduled clocks plus populated track groups creates your automated playout log.