Hydelings are the fans of YouTube star Kayley Hyde (owlssayhooot). The term was coined by the fans of Kayley Hyde via the twitter account KayleyHydeArmy and has since been their unofficial collective name.
When a person has both a boy/girlfriend and another friend they flirt constantly with. That way, if the boy/girlfriendrelationship doesn't work out, there's another person in reserve to ensure against singledom.