1. an activity done regularly in one's leisure time for pleasure.
If you enjoy the activity then it is neither pointless nor a waste of time since the primary purpose is enjoyment. If you don't enjoy it, it's not a hobby.
No doubt these posts could be your hobby; you do it for pleasure but it's otherwise just a pointless waste of time.
Hedonism — the doctrine that pleasure or happiness is the sole or chief good in life.
"It's not a waste of time since the primary purpose is enjoyment" — in that sentence you place enjoyment above any other benefits the activity might have (but most often does not). Hence, it's a hedonistic approach.