Now in Google Spreadsheets, some people are able to set "notification rules" that keep you up-to-speed with changes being made on spreadsheets. This handy feature gives you the ability to be notified on a daily or an as-it-happens basis when these specific events are triggered:
- Anything in your spreadsheet changes
- Anything on a specific sheet changes
- A specific cell or a range of cells changes
- Collaborators are added or removed
- User submits a form
Both collaborators and viewers are able to set up notifications, however only collaborators will be able to see the usernames attached to updates.