There are a few volleyball forums in cyberspace, but the hands down favorite is VolleyTalk. It is an anonymous board with many enthusiastic volleyball coaches, players, parents and fans that offer their advice about anything volleyball. The only issue is the website name: http://volleytalk.proboards.com/index.cgi The URL is not easy to remember. When my bookmarks aren't readily available, I often have to do a google search to find it. It's worth the 'hassle'. I highly recommend checking it out.
There are a few others that you may find of interest:
Volleyball Magazine has a good following for men's and junior boy's volleyball. I will add that Volleyball Magazine is coming out with a new print and online format to the magazine. There have been mixed reviews as the publication is attempting a more mainstream media approach using volleyball as its avenue. I hope it helps to bring in new volleyball fans.
Volleyball Forums treads water with their forum. It has become a place where an RSS feed posts the latest news from around the volleyball world.
Volleyball.com's forum was treading water for a while too, but I think it has sunk. There might still be some good information within old posts.
Enjoy the discussion boards, quite a bit can be learned from them (although take-in the information with a grain of salt), and post away...carefully 😉