I also just checked Marriott's page and it seems to say that points earned via social media, i.e. tweeting and stuff, don't count as "earning" towards keeping your miles from expiring. We might want to put it in the wiki, as that's technically earning activity (you do get more miles/points) but not activity that can prolong the life of your miles. I'm not sure if other hotels also do social media promotions (I've only seen marriott do them) or what their rules would be, but maybe for some hotels/airlines we should put in some details about what exactly counts as "earning"?