Product-Qualified Lead (PQL)
A product-qualified lead is a user who has experienced real value inside your product, usually on a free trial or freemium plan, and whose behaviour signals they're ready to buy. Unlike a marketing-qualified lead (who downloaded an ebook) or a sales-qualified lead (who booked a call), a PQL is defined by what they actually did: hit a usage threshold, invited teammates, connected an integration, or crossed a plan limit.
For a lean founder this is the cleanest signal you have. The product itself does the qualifying, so you spend sales effort only on accounts already showing intent. The work is defining the right threshold, which means knowing which in-product actions correlate with conversion. Get that right and a single founder can run a sales-assisted motion at surprising scale, because you only ever talk to people who are halfway sold already.