Passage: The Gmail Labs feature, introduced on June 5, 2008, allows users to test new or experimental features of Gmail. Users can enable or disable Labs features selectively and provide feedback about each of them. This allows Gmail engineers to obtain user input about new features to improve them and also to assess their popularity.Popular features, like the "Undo Send" option, often "graduate" from Gmail Labs to become a formal setting in Gmail.All Labs features are experimental and are subject to termination at any time.

Question: What year was Gmail Labs introduced?
2008