The email notification is probably the biggest thing. My Gmail account right now primarily consists of notifications. Which gives me comfort that others are see

The email notification is probably the biggest thing. My Gmail account right now primarily consists of notifications. Which gives me comfort that others are seeing these as well. So I know that when I use various social media sites, others will know when I've interacted. Twitter's @reply is another good tool, one that doesn't have the email notification. Without those types of attention hooks, I'd be less likely to use the sites.