Do you know what conversion tracking is? Google Adwords and Analytics can measure impressions, clicks, Click-Through-Rate (CTR), Total cost, Cost-Per-Click (CPC), etc. but ultimately what you really want to know is how people are engaging on your site. Are they making contact? Are they buying anything? Measuring the behaviour of users on your site is one the most essential items of website optimisation.
If you approach Pay-Per-Click (PPC) from the perspective of generating traffic, you are essentially throwing money into a black hole, branding is important, but, sales are better. Measuring conversions boils down to understanding your return on investment (ROI).
Conversion tracking involves placing a small bit of code on a certain page of your website; the code tracks the user from a start point to a determined end result. If the user completes all the steps the code requires a successful conversion is registered. Goals can be something as simple as filling in a form and clicking send or it could be something more tangible like buying something from your site.
Using conversion tracking is not to track how often interactions are made on your site but also to determine how your site can be improved and in turn increase the amount of conversions on your site.