Savvy brick-and-mortar marketers know bathrooms are a profit center. The Internet is no different. Required-yet-boring functionality like order confirmations, logout screens, and password reminders are like bathrooms in real life. My local coffee shop knows when customers are pissing they’re a captive audience. Hence the happy-hour-upsell above the urinal.

It doesn’t matter where.
Whenever you have your customer’s attention, you should be talking to them.