I manage anxiety on a daily basis. In addition to being an inherently anxious person, I also do things most other human beings do, like spend time interacting with friends and family on Facebook. I've noticed that (being an anxious individual) I use social media differently than someone who doesn't deal with chronic anxiety.
For example, I've been told that I tend to "post a lot" on Facebook. Someone who doesn't have anxiety might log on to Facebook one to two times a day. I, on the other hand, check Facebook multiple times per day. I might be walking down the street and see a funny sign or a beautiful plant that I just need to photo of with my IPhone and share on social media, whether that be Facebook or Twitter.
I suppose it's connected to impulsivity. I need to share whatever the content is right away or else I might forget and the really funny e-card will go unshared. This results in my Facebook wall having a lot of content on it.
Another thing I am guilty of on Facebook is tagging people in posts. If I like you, and I know your personality, I want you to see this particular post because I feel that it's relevant to you. In my mind, if I don't tag you in a post you might miss it! It makes me anxious to think that you may not see (what I feel) is something that relates to you.