My guess is that you wonderful folks have statistical tools that analyse hits and postings to enable you to make decisions about the site and its effectiveness.
I had a quick look at the members section the other night and found that about half the members never make a post and about a quarter make one or two posts (usually an intro) and are never heard from again. As the number of posts rise the number of people making them dwindles markedly. In fact I graphed it and it appears that the entire load (of responding to posts) is carried by very few people.
So, taking a risk, I selected a member with only intro postings a couple of months ago and sent a private message asking how he was doing. Fortunately he was delighted to receive it and reported positively about his progress.
That got me thinking about the number of members who intro themselves in a cry for help but don't quite find the answer they seek, even though it may be only one click away.
My suggestion/question is: Is there any way of following up on inactive members who maybe in despair? One possibility might be a "Last post date" in the member profile.
Just a thought.