Measuring conversion metrics is often overwhelming. A Floodlight tag is a piece of HTML code generated in DoubleClick Campaign Manager that can help you to keep track and report the activities that are happening on your website.
In Ad Operations (Ad Ops), an activity can be referred to as a conversion. For every activity that takes place, a tag gets generated. DoubleClick Search can automatically generate a floodlight tag, which you will need to embed in a particular place of your website from where you want to track the activities. So when a visitor clicks on an ad and lands on a page, the tag sends information about the conversion back to the DS and the DCM.