SharePoint Online 2013 - Suggested sites to follow

The new top navigation of SharePoint Online 2013 contains the Sites tab:

There is a section called Suggested sites to follow (in yellow). Unfortunately nothing is shown in my tenant. I asked Microsoft how this feed gets its suggestions. Here is the answer:

• Sites that are being followed by your colleagues.
• Sites that are being followed by people you're following will tend to be recommended to you.
• Sites that are being followed by a large number of people in your organization.
• Sites that you have modified recently.

Posted in: SharePoint Online 2013