I think if you were to try to quantify the success of a thread, you could do so by taking the number of posts divided by the number of views. This would give you a number between 0 and 1, where 1 is the highest possible success level of a thread.

Cases:

For thread 1 (t1), there are 20 posts (p=20) and 20 views (v=20).

Success is defined as S = p/v, so S_t1 = 20/20 = 1. Every single person who viewed this thread made a post in response.


For thread 2 (t2), there are 10 posts (p=10) and 100 views (v=100).

Success is defined as S = p/v, so S_t1 = 10/100 = 0.10 For every 10 views, there was 1 response.

IMO.