[mhennessy]

So what about the case when established members start threads yet don't come back to answer all the questions that arose or to give feedback on suggestions? Despite being active elsewhere on the forum...

It's not just on forums though. If you contact me via my website, one of the "terms and conditions" - for what they're worth - is that you must acknowledge my replies in some form. I only hear back from about 40% of people. Like Dave suggests, I sometimes send quick replies with requests for more info before getting into the "meat" of the conversation - that at least establishes that email is working, and when further replies aren't forthcoming I know it's not a technical fault (emails aren't 100% reliable by any means, and nor are people when typing and retyping email addresses).

In the past I've produced near-complete designs that were neatly drawn up and emailed to people, and no replies come back. Nor did responses to my "chase" emails - despite the fact emails were successfully exchanged previously. One such example was for a forum member, which shows that this sort of thing is not necessarily a characteristic of the social media generation. We all have limited time and competing priorities, so time donated to forums and email conversations should at least be acknowledged.

I find keeping on top of emails much harder than keeping on top of threads and PMs on a handful of forums. I suggest on my website that people email me again if I don't respond after a couple of weeks. I am human, after all. With that in mind, I always reply to people who ask me questions nicely. You would not believe some of the emails I get!