Contributing factors include, but are certainly not limited to, the following:
Friends with significant others
Changing Facebook statuses
I will confess that watching Facebook relationship statuses change almost on a weekly basis is… enervating. Watching countless "friends" ('cause let's be honest, no one is FRIENDS with all their Facebook "friends") change their relationship statuses from "in a relationship" to "engaged" makes me wonder, hmmm…. what is it about me?