Chapter 6 of Heath's Made to Stick introduced the idea that the process for great ideas to "stick" is much more than an empirical, step-by-step formula to be completed by any one with the motivation.  Rather, one of the most vital aspects of a successful idea is the ability to make a connection with the audience on different levels, especially an emotional one.  Through real-life examples and stories, Heath is able to illustrate the value of making this connection by making us (the reader) care.  He explains that like stories, valuable ideas provide simulation and inspiration, which instigate action, and are understood as credible as well as emotional.  Essentially, the more someone cares about your story, the more likely it is to stick and the more likely people are to take actions aligned with progressing your idea into a successful reality.

Heath also lays out the acronym, SUCCES, as a checklist in determining an idea's potential.  He names the following qualities as necessary: simple, unexpected, concrete, credible, emotional, and story.  Again, these characteristics help facilitate that connection with the audience that allows them to simulate the experience and be inspired to care and take action.

I think these explanations for what makes an idea great can be somewhat sub-conscious for the participant; for example, when I go to a social media website that I enjoy, it isn't because I'm thinking to myself, "wow, this site is so simple, unexpected, concrete, credible, and emotional".  However, this does help explain more why certain social media sites do not work and do not appeal to me.  Sometimes I visit a site and for no particular reason, it doesn't "stick" with me; now that I understand what exactly makes a great idea, I can see that these "bad" sites aren't making a connection with me, they aren't pulling me in emotionally.