If you have ever stood in the rain wondering where the nearest umbrella shop is, then the latest Google patent may interest you.
The search giant has secured intellectual rights to a system that would serve ads based on environmental conditions.
Google said forward-looking patents were useful for its portfolio, but it had no current plans to act on it.
But privacy advocates have warned it could set a dangerous precedent.
The patent, first reported by PC World magazine, potentially paves the way for a mobile phone fitted with sensors that would allow it to record data such as temperature, humidity, light, and sound or air composition, which would trigger relevant adverts.
"Advertisements for air conditioners can be sent to users located at regions having temperatures above a first threshold, while advertisements for winter overcoats can be sent to users located at regions having temperatures below a second threshold," explains the patent document.