When I'm replying to a user or two on my community, I like to keep the discussion growing and expanding by asking the user or two another question or so, that way, they reply and the thread continues. But, are you like me? Do you ask your members questions when you're talking to them?
I always make my topics full of questions. I also talk in a personal voice... Example: Instead of talking about something to an audience, I talk to the audience using words like "You" and "me" and "we" and so forth. If you talk in your personal voice as if it is a one on one conversation, people are more likely to talk back to you. Questions encourage further communications too so be sure to add them. Add a couple, give plenty of options for people to respond to what you have to say to them
I ask my users questions all the time, and that's actually something I've learned from you by observing how you manage your forum.