In the gamemember

Guild › Activity

What happened in the guild in the last 7 days, in a few lines.

In your game: Guild › Activity

What it does: A summary of the last week: new members, who left or was removed, raids logged, items handed out, the change in your points, who reached the level cap, the next event, new bulletin notices and new polls. These are the same lines as the summary that appears when you log in.
Who sees it: Everyone. Officers also see trials ready for a decision and how many members are inactive.
Where to find it: In the window (J or /gos), Guild tab, Activity sub-tab.

Shows only the last 7 days. With nothing in that period, it shows Nothing new in the last 7 days.
New members appear with up to 3 names and +N for the rest.
Who left and who was removed appear as a count, not name by name.
From the bulletin, up to 3 new notices are included.
An event in the next 24 hours appears as soon, with the day and time.

Promotions and demotions do not appear here. The full log is in Leadership, which is officer-only.
A new member is someone your addon saw for the first time, not the date the person joined the guild.