Facebook generates a Post record when I rename a group's name or just an ActivityItem? My question is more about relational database scheme.

I have in mind two tables for it:

Posts
Activities
Where when I post a a status message it probably creates a record for a Post and an Activity representing this (for build the feed and represent notifications).

Well, in case of renaming the name of a facebook's group I started to have this question.

Is created ("simulated") a Post record for a name changes or just and activity record?
While I can't comment how Facebook works internally, in terms of relational design, a normalized schema would have these two actions in separate tables.

This would be done because the other bits of information associated with each action would be very different.

Changing a group's name would probably involve inserting a history record with the old name, and updating the current record with the new name. Notifications could have other things associated, such as comments and likes.