What was the Google Street View Wi-Fi data-collection scandal?

Question

Accepted Answer

Between 2008–2010, Street View cars deliberately recorded Wi-Fi data (SSIDs, MAC addresses, even unencrypted payloads) to build a global Wi-Fi positioning database — first dismissed as an accident, later shown to be intentional.
Google Street View vehicles, while photographing streets, systematically collected Wi-Fi data — including SSIDs, MAC addresses, and partly even unencrypted user data sniffed from the air.
The scandal: this collection was intentional but initially framed as an accidental error. It later emerged the software was deliberately programmed to capture Wi-Fi packets.
The purpose: the harvested Wi-Fi data enables precise positioning even without GPS — Google built a global database for Wi-Fi-based location.
Tip: This is the origin story of why Wi-Fi positioning is so accurate: someone had to drive around mapping every router's MAC address to a physical location first.
Go deeper:

Google Street View privacy concerns (Wikipedia) — the Wi-Fi payload collection, complaints and deletions.