A bit of history dredged from my memory.
The forum used to be quite active (several years ago). At some stage the flight connect calendar was either added or enhanced and FTers were recommended to use that instead. Unfortunately the flight connect calendar itself has problems. So a number of forums compensated by having their own threads (eg LH, SQ), or off-FT tools (eg BA97) to organise meetups.
I admit I have very rarely visited the itineraries forum for the past few years. I use a number of the special threads and tools instead. From time to time I see from the forum listing page the odd lost post. My impression is the forum is very confusing to newbies. The lack of oversight by other FTers means queries can languish there and I'd guess there may be some new FTers turned off by the experience and then leave for good.