Lets say you want to track individual keyword performance, and separately track ad copy performance. If you’re using Adwords, you don’t need to place tracking code on the destination URL’s to track the performance of each keyword, and separate tracking for the performance of each ad.
You just need to make sure you link your Google Adwords account to your Google Analytics account. Google will automatically pass the gclid code, thru Auto-Tagging.
Google created auto-tagging (turned “on” by default) so that large and small accounts could easily see how their AdWords keywords were performing from click to conversion and back to cost. Auto-tagging automatically associates a parameter with the click on your ad which then allows Analytics to report the details of the click, including which AdWords keywords brought a visitor to your site, which campaign that keyword was from, and how much that click cost. This information can then be associated with richer information within your Analytics reports, such as goal or e-commerce conversions, to give you a sense of how your AdWords spending is really performing.
The screenshot below shows exactly where you will find this within your Adwords admin:
If you’re running 2 ads per adgroup, then in order to track the ad copy performance, just make sure the Headline is different for each ad. The description can be the same. But, the Headline can’t. Because that is what will appear in Google Analytics. The difference can be as subtle as a semi-colon, or a period, as long as they’re different headlines.
You can see that data under “Traffic Sources” –> “Ad Versions”.
If you are running non-adwords campaigns (eg: Yahoo, MSN, email, banners, etc), then you will need to tag your URL’s with tracking code.