1. There's no way to have a general email list right now. I think the direction we're pushing developers towards is having them write to their devlog (which might not be appropriately named) to announce stuff. Then we'll handle sending out notifications to people that are interested. I like this better than email because then it's forever available online, and not lost to people's inboxes. Feel free to use the email feature, but I don't think it's the kind of thing you should send too often, since it is more obtrusive and people could be likely to unsubscribe. I think the best use case for email is using it to tell buyers things that are relevant to them.
2. There are definitely message boards that are active. The most active ones I can think of are doing some sort of closed access/refinery release where they're collecting feedback from people. (Game jam boards are also pretty active too) I don't know the best way to get people to post to yours, you'll have to find some way to encourage them. If there's some feature of itch.io we could add to encourage more posting tell me. Also, if you end up doing something that works for you, tell us, so I can share that info with others.
The most common uses of message boards I've seen so far are:
- People reporting bugs
- People sharing ideas about stuff they'd like to see in the game
- Streamers/lets players sharing links to their videos
What kind of engagement are you looking for? Is it included in the list above, or is there something else?
Sometimes the best way to get people to start posting is to prompt them to by creating topics asking about certain aspects of your game.
We try to show players the message board as much as we can, it's on the game's page, and it can show up on their download page as well. If you think there's another place where we can put it to encourage people to post say so.