1. Each to their own I suppose. For an established site such as this I'm surprised you feel the need to deliberately force people back to the site in that way but that's your call. In my experience of other sites, including having moderator rights on EA forums, people will go back to the forum anyway when they have time and it's just annoying when you click to see a reply to a message that's not a constructive reply. More so when you're viewing forums from somewhere such as at work, looking at emails is fine but viewing forums every 10 mins when there's a reply to a post isn't as easy to get away with.
2. I suppose you will always get people like that.
3. On other sites you can set it such that you are sent an email once until you next view the forums or sent an email for every single reply.
I was only asking cause I'm a pretty experienced forum user, despite me only having a few posts on this forum, and it would be nice to get this one working the same as others, from a personal point of view. But it's not a problem at all, I'm happy to go with what you thinks best for this particular site. See you around.