You already know that calls to action are a great way to keep your users from falling deep into an existential void after they watch your video. We're huge fans of tracking everything here at Wistia, and calls to action are no exception. How can you keep an eye on whether viewers of your video are following your calls to action? Here are a couple of ways that you can take your calls to action to the next level.
URL shortening services like bit.ly are more than just a method for making messy-looking links more pretty. You can also see how many clicks a link is getting from a particular location, and you can compare the number of people finishing the video (from Wistia's analytics) to the number that are clicking your post-roll links. Services like bit.ly are a really easy way to track which paths people are taking to a particular page.
Another thing that you can try is using UTM codes (a.k.a. Urchen Tracking Module codes), which can be tracked easily in Google Analytics (and you can even combine their power with bit.ly tracking by putting UTM code URLs into bit.ly!). You can use Google's URL Builder tool to filter analytics by UTM categories like source, medium, and content. For example, if you have a video in a few different places, you can give each post-roll URL a different "source" code. Multiple versions of the same video could be differentiated by different "content" codes.
Another added benefit of using UTM codes with Google Analytics is that you can track beyond just the initial call-to-action click and keep track of whether people are actually converting -- signing up for trials, filling out contact forms, etc.
Regardless of what tools you use to track your users, it's hard to argue against connecting the dots of how video-watching is helping you to create prospects and increase conversions.