1. Click on the blue Search button in the upper right without entering any search terms. (or go to https://discussions.apple.com/search )
2. Choose the More Options button and enter MacBook Air in the Restrict to a Community, Project or Group field.
3. Enter 'external display' in the Search field.
4. Click 'Search.'
Optionally, filter by date.
The above search will give you these results.