Tasks are a powerful tool when sending a campaign to a contact, especially if your sales process is multi-channel/touch.
Task to send an Email and Task to Call a contact are the most common uses for Tasks in Campaigns.
You can also make a "Task to Inmail" a contact on LinkedIn if that's part of your workflow. You can also make a custom task to remind you to invite them to a happy hour, ask about their charity event, or check-in after game 5, etc.
The most important thing about Tasks in Campaigns, you have to complete the task in order to trigger the next step.
Tasks will always be associated with each individual in the campaign. This means you have to go into each person and close the task in order for their individual campaign to proceed.
You can manage your tasks in: the Tasks tab of your Campaign in Campaigns 2.0, directly from your Command Center, or from the Tasks section of the Live Feed. Additionally, you can also manage your tasks from Salesforce.