I can consult you on this question. Together we can come to a right answer. or
Something so does not leave or
You were mistaken, it is obvious. or
I can not participate now in discussion - it is very occupied. I will return - I will necessarily express the opinion on this question. or
I consider, that the theme is rather interesting. I suggest all to take part in discussion more actively. or
I can speak much on this theme. or
It absolutely agree with the previous message or
You obviously were mistaken or
Bravo, fantasy)))) or
In my opinion you commit an error. I can defend the position. Write to me in PM, we will talk. or