User timeline
A user timeline is the actual chronology of what someone is doing as they work toward whatever they're trying to accomplish. Ask the user what they were up to on a Tuesday afternoon and they'd say "getting the quarterly invoices out" or "figuring out where we're staying in Lisbon." That's the timeline: their activity, on their schedule, in their words, as opposed to the sequence of steps the company wants them to take.
Definition
The user's lived chronology of their pursuit — the temporal frame within which their transitions and routes occur.
The user's timeline is the real timeline
Users show up on their own timeline, driven by their own reasons for engaging. They don't know about, and don't care about, the company's narrative arc — funding rounds, feature releases, internal roadmap. Their chronology runs from whatever moment the pursuit became live for them through whatever sequence of states gets them toward what they're after.
Describing this timeline accurately is the foundation the rest of the framework rests on. Most "customer-first" framings still treat the provider-biased timeline as dominant and ask how to incorporate user input into it. The framework reverses this: the user's timeline is the real timeline, and the provider's job is to align with it well enough that user progression drives business progression.
What the timeline frames
The timeline is the temporal axis of the pursuit. Transitions are the structural units occurring within it — discrete state-to-state movements. Routes are the trajectory the user actually takes across available affordances to traverse those transitions. Timeline, transition, and route are three different cuts of the same activity: timeline names when, transition names what state-changes, route names how they get traversed.
Span and nesting couple. Larger transitions span longer timelines because they contain their sub-transitions' timelines. A user's "switch invoicing tools" transition spans weeks; the "set up first invoice" sub-transition inside it spans an afternoon.
Abstractions of the timeline
Journey maps, funnels, and Pirate Metrics (AARRR) are abstractions of the user timeline, not the timeline itself. Some are more faithful than others; AARRR especially is a reorganization onto the company's stack, with categories like "activated" or "retained" that describe what the company wants the user to have done rather than anything the user would recognize as their own activity. The framework treats these abstractions as suspect by default and works from direct observation of what users are doing.
Example
A freelance designer realizes invoicing in Word is costing her late payments and unpaid hours. She searches for invoicing software, lands on three candidates, signs up for one, tries to send her first invoice, hits a snag with tax configuration, works through it, sends the invoice, gets paid faster than usual, and decides to stay subscribed for the next month.
That entire sequence — from problem recognition through getting paid and renewing — is her timeline. The provider's own timeline (Q2 payments-feature launch, Series A close, a hiring push) runs in parallel but is invisible to her. The provider's work is to align affordances against her chronology, not its own.