Why should you close a group or thread on
1. Dead groups can be discouraging to a new user when they come to your group.
2. Nice and potentially engaging messages can go into the wrong group
3. Too many groups can be confusing and difficult to navigate. No one likes confusing layouts.
4. Lesser groups mean more number of people active on one. This allows you to focus your efforts accordingly.
Decide which groups are best for your online community.