You're probably under pressure to use the latest technology. Your client wants to use it, your boss wants to use it and your vendor certainly wants you to use it.
A small percentage of the people you're trying to reach want to use it too.
The problem with the latest technology is that most people don't use it yet. Worse, most people probably don't want to learn how to use it. It's too new, no mainstream appeal. You're cutting down on potential members by using something shinier.
Simply being old is not a good enough reason to replace a medium that everyone knows how to use. E-mailing lists, forums and chat-rooms still work perfectly fine.
It's nearly always better to pick a medium that most of your community knows how to use.