Gmail labs is a place for testing experimental features that are not quite ready to roll out as a standard feature. These things may change, break or disappear at any time. To activate the to-do list also known as Tasks:

Click on settings within gmail
Click on Labs
Enable Tasks
Click Save Changes near the bottom of the page

On [...]

Seconds add up to minutes, minutes add up to hours, and hours add up to days. How much time can be saved by using shortcuts keys? Not sure, do the math. Lots of littles add up to a big. Anyway, I know it may take a little time to learn the shortcut keys but it [...]