Great point about slacktivism being due of a lower barrier to supporting a cause.<p>However, I doubt that a higher barrier would cause the "slacktivists" to engage more, rather than just not engage at all anymore.<p>Maybe one day microdonations (Flattr/CentUp/Gittip) will help lower the barrier to actually donating to a cause. To the point where donating is as easy as hitting a Like button.