Simple. You make a story of the thought of the previous post. Example:
Topic of post 1: Tree's are bad.
Then Post 2: One day, I went out and saw a big a tree. I was like, "Dude, I'm gonna do it... I'm gonna climb it."
So then I climbed it. Once I got like halfway up, It started to fall. Then it fell on the road and hit the trunk of a car. Wow... Awesome...
Topic: Would you love a monsterman?
And it goes on. So here it goes.
The starting topic: History is so 100 years ago.