Karma comments were not migrated across Max. Completely different software so some things had to go (judging by the apparent confusion with the new reputation system, I wish it had all gone missing
).
Membergroups allow us to offer access to groups that are invitation only, such as the Glamour forum. You can request access via the membergroup section in your control panel.
As you were already a member on the previous software you don't need to do it again (one thing that did work well in the migration
).