We used to use UTM codes with Google Analytics. It ended up being too much work, so no one on the team would consistently do them. read more
Ad trackers normally help you discover how many views, clicks and conversions have been generated from your ads, whether they are banners, emails, text-links, posts, etc. Most advanced services, like ClickMeter, also provide additional info about the source and let you track links and compare different campaigns. read more