I have developed a forum using Xenforo (I think DP uses that software too). So far I have edited and customise somethings but I realise some bad things with forum software. One of the bad things about forum software is that they bloats too many options for the users to do. For example in the registration page there are too many options to register like gender or time zone preference. If you go to sites like Tumblr, Pinterest, Twitter, etc you don't see this kind of options to register. They make it easy for the user to enter the site, not put a wall before the users. So reactive and disable the visibility of those options. They can add those other things later. Just leave: Username Password Email Another thing is the email confirm, some social networks don't use this. I recommend you for the first users not to use the email confirm (because maybe it will just go to their spam inbox). I understand that for spammer reasons you want to turn this on but while you begin your only concern should be to get to 1000 users (preferably active ones). Feel free to try the registration in my site thegamedealers . com and let me know how it goes. I also turn on registrations with Twitter and Facebook logins that's even easier since it's just one button to enter.
I think it is better to have the email confirmation to ensure they are valid users. If in future you do a mail out to the members, you don't end up with a tonne of bounced emails from people using fake email addresses. It is also an extra step to stop nuisance members or at least slow them down from coming back time and time again. It doesn't stop the spambots though, they have workarounds.
But why if you are starting out would want users to NOT register to the site. You want the opposite. I understand that you do this when you got more than 100 users at least. But I agree with you spambots can get workarounds that's a shame.
I think if your content is worthwhile you will have users fill out whatever they have to in order to join the community. Its not a forum unless there is something worth reading or discussing at the end of the day.
What a good answer! I will focus on making more good content to populate a little more the forum I started. I want to like your post but don't see the like message button, I am missing something with the DP interface?
Increase topics/post in your website which attract the user for more sign ups. And try to easy sign up with google/fb.