I think one of the most overlooked things in engaging customers on the web is a good landing page. Rather than directing customers through web / SM advertising, blog entries and posts to your home page, the copy should give them an offer to take them to the web page, and the landing page should fulfill that offer with no further hoops. The page should also provide a call to action that takes them to the next step. For example, an article or SM Posts might give a synopsis, like top 3 things to consider with a link to the top 10 things to consider. The landing page would send out the top 10 things "white paper" to a provided email address, and then give an opportunity to sign up for a newsletter.
Landing pages can incorporate UTM so can be reuses and still track origination. They can also easily be used to A/B test different offers for engagement.