Sailthru can track the number of people who click on your emails, which is very useful as a measure of user response to your emails. We recommend turning on link tracking in almost all cases. If link tracking is not turned on, Sailthru cannot measure clicks.
To turn on link tracking, simply make sure that the Link Tracking? option is set to "Yes" in the Details tab of the template or campaign editor. All links will automatically be rewritten to go to the Link Domain you have set on your Settings Page.
If you turn on Use Google Analytics? then all links will add certain special utm_ parameters that will allow you to see your traffic coming from emails in Google Analytics. You can turn on this setting independent of the Link Tracking setting. If you are using Google Analytics on your site, it is highly recommended.