there should autochange the "title of reply post" to " my reply content is..."

that means below:

• ...when you got lots of reply posts ,there got so many same title using your topic title; that's crazy noise
  ... it shoule be like that
  
• hey all it's my topic title
  
• reply: awesome title but i think ...
  
• reply : hey all you think is but ...
  
  
  

I mean there need't be a "title input form " on reply form.
just catch some words of the first sentence of the reply to be a reply title instead of "reply:the topic title"

that will give a guest viewing whole thread some tips of what they are talking .