Gmail added a lightweight tool to track your pending task, this will spice up your inbox if you are really unhinged to track your to-do’s.
How to enable task?
Go to settings link and navigate Labs tab. You can see an option (radio button) for enable / disable.
Does the application suits you?
If you are a serious user those who are very busy with works and you are not able to track your to-do’s this is the right application. In the busy life, marking our to-do is only method to get things done.
After adding the application in your mailbox you can add / edit / remove tasks. Moreover you can add email as task also.

Here is the snapshot of gmail task.

Nice information . I have this feature in my mobile itself !!