For many people, the point is posting family photos and cat pics under their real name, for childhood friends and relatives, discussing technical details of some computer game in a slang-rich game forum, and maybe discussing hardcore [insert your favorite bogeyman here] on some forum of like-minded people.

All these three personalities need not be connected in any way, nor need they contradict each other in what they say. They are just for different and unrelated facets of one's life.