Ask for the Participant's interest following his/her registration

One of our clients requested that we automated the grouping of users according to to conditions he sets. For instance, the administration create a group called "Neighbourhood A". Every participant that declares living in "Neighbourhood A" is automatically incorporated in the said group. This request comes from the fact it would enable him to contact much more easily every participant belonging to the group if a participatory process concerns them. He feels it could also ease the invitation to private participatory processes. We think automate participant grouping is a (very) dangerous path to follow. Given that now a participant can choose his interests and that the ability to send a newsletter to a selective group of users will come soon, we thought about asking a participant's interests on his arrival on the platform. Our proposition could take 2 shapes : 1. Interests are incorporated in the registration form. 2. Add a second step to the registration journey. Following his registration, the participant is redirected to his interests page. Our preference goes for the second solution as it avoids the risk to overload the sign up form without adding to many steps to complete registration. It is still a "rough" proposal but we wanted to know if it raises interest among the community. Moreover we feel it could be an improvement for the participant as well. He/she early on about which topics he wants to be involved with.