One thing that struck me was the average number of posts per user. Isn't that a bit odd? The number of total users is significantly different but just over 1 post per member. That data seems to reflect a very low involvement of the users on the forum. Of course just as you could say on XY's forum, there are some that have hundreds and even thousands of posts and many others have a small number. But, the average is still very low. Possibly they are automatically added to the forum listing just for becoming trial members or registered users. That might explain their low average of posts per forum member. I don't have TC so I don't know and there are other stats that are needed to properly analyse the comparison like total registered users and trial users of TC.
TC forum's membership is approximately 43 times greater than XY's yet they have a little over twice the number of total posts.