As a general principle, the more information you seek from members the fewer will complete the registration form.
Some automatically assume this is a bad thing and reduce the information sought to just an email address and password.
The reality is the registration form is one of many tools you use to attract the members you want in your community and the kind of mindset they’re in when they arrive.
If you simply want anyone and everyone, you will get members who haven’t had to think what they want from (or what they can contribute to) the community. That will be reflected in your discussions.
But adding the right kind of friction helps shape the kind of community you’re creating
Take a look at this signup form below (for a very meta community for community managers).
There is a hodgepodge of good and bad ideas here.
The location, mobile number(!), job title, and favourite TV show can probably be removed.
Unless you’re limiting membership by any of these categories, they don’t change the mindset of members or act as a natural filter for members.
The ‘what are you seeking’, ‘what can you offer’, and ‘what is your proudest accomplishment’ are examples of good friction (although the former two need more options).
These questions make people think about what they want from the group, prime them to offer something to the group, and encourage people to share what they’re proud about. It creates the platform for a very unique sort of community.
Just because you can reduce friction and get more people to complete the registration form doesn’t mean more people will participate in a productive way. Carefully adding friction can help nurture a far better community.