I have a forum that started out with about 75 core members and now averages about one new member daily. I feel that a new member daily is certainly good enough for my needs. What do you think? Also, what would be a good percent for active members (compared to total members)? While I am getting a new member daily, only about 20% are truly active (within the last month). Not as good as my registration rates though...
No of new joinees depends on the niche and the marketing your forum gets but... I think 20% active members is good enough... my technical topic forum has a rate of 10 members joining per day but would say only < 10% members are active