Apps4Flip-Admin I don't know if you're interested in switching, but [Login to see the link] is a great free forum you can use (it's what DansDeals uses). It's very easy to quote other posts, it's a simple software that doesn't take crazy to load, it's pretty customizable (I think). Also, instead of just having different color Tags, when someone enters the Forum, they can choose what board they want to enter. (the home screen has a list of boards: LG Classic, ADB, Filtering, etc.) Each person has an option to view most recent unread posts. Also, you can make contributors get points based off how many posts they have, and how many likes (and it shows you have a good reputation). Also, I think you can make your own points category (EG, DansDeals gives a Hat Tips point for everyone who posts a deal that makes it to the main site). Also, I've never experienced the Admin side, but I think admins have a lot of control.
In terms of flip phones, it should be supported on all the 4G phones (I think, if you wanna test it go to forums.dansdeals.com). However, on every phone (smart phones included) you have to scroll left and right (or make screen smaller) because it works best on computers. But it wouldn't be terrible at all, I suggest you try it on forums.dansdeals.com to get a feel. You can see [Login to see the link] for some solutions to fit better with a phone.
I think it's also compatible to move the current forum to this new one. In general, it's a pretty nice Fourm, and if you are ever considering switching I'd try it (I know, it's not easy to keep switching).