Would be great if the "Mass Update Tasks + Activities Tab + Create Multiple Tasks" app @ https://appexchange.salesforce.com/listingDetail?listingId=a0N30000003IleFEAS can send an e-mail to users who receive a task if they have 'Email me when someone assigns me a task' activated in their profile:

- Go to username > My settings

- Expand ‘Calendar and Reminders’ section

- Click on ‘Activity Reminders’

- Confirm that under ‘Email Settings’ ‘Email me when someone assigns me a task’ is checked