A behavioral offset(though not necessarily a detrimental one) in which a person will treat a random person they meet with(and probably helped with once or twice in their lives) as if they were best friends. Typical Myspace Syndrome can be identified in superfluously affectionate behavior(ie: often demanded big hugs when they meet, etc)

How the two meet is by no means limited to just adding each other as friends on Myspace/Facebook/etc.

When you eat dirt for the first time and leave your family to build a shack in the woods