What does it mean that ubiquitous capture tools?

You need capture tools available in every context where you think — desk, commute, shower, conversation, bed. A gap in coverage is a gap in your thinking.

Example: You solve a thorny architecture problem in the shower, but your phone is in the bedroom and your notebook is downstairs. By the time you towel off and find something to write with, the specific connection that made the solution work has degraded into a vague sense that you 'had something good.' You didn't fail at thinking. You failed at tool placement. The insight was real. Your environment wasn't ready for it.

Try this: Map every context where you regularly think: desk, commute, walking, shower, bed, meetings, gym, cooking. For each one, write down your current capture tool and how many seconds it takes to go from thought to externalized text (or voice). Any context over 10 seconds is a leak. Any context with no tool is a hole. Fix the worst one today — install a widget, place a waterproof notepad, put index cards in your jacket pocket.