Google Analytics lets you create custom campaigns and with the help of this feature you can improve your social media marketing to a great extent, according to this blog post on Social Media Examiner.
The simplest way of achieving this is assigning customer campaign tags to the links that you share on social networking websites and elsewhere. This feature can also be used to track your AdWords and other PPC campaigns.
But why do you need to monitor your social media marketing campaigns?
Analytics give you an in-depth insight of exactly which social networking website is sending you more traffic and how much time people spend on your website from that particular source. You can also track the performance of individual updates. For instance you post a link from your website on Facebook on a particular date and at a particular time. You want to see how much buzz that update was able to create not just in terms of getting likes and comments on Facebook, but also sending traffic to your website. In the absence of a custom tag all your analytics data tells you is how much traffic Facebook sent you. But with a custom tag you can find out exactly how much traffic a particular update generated for your website.
Custom campaigns also provide you the usual data that comes with every other campaign such as from which region of the world most of your clicks came, for how long people stayed on your website, from which page they left your website, and so on.