In a thread, because we cant create subthreads, the comment menu should have a new item called "quote reply".

"Quote Reply" should allow the user to add a new comment with reference from the comment he is replying.

A : I like cars.
A : Wanna go for pizza? <-- "Quote Reply"
B : I like Ferrari.
B : "Wanna go for pizza?"

 Yes. Pizza is a great idea.