How do I see who has set up an alert in SharePoint?

Users were supposed to have created an alert so that they received an email about any additions to the Company Announcements page in SharePoint.

We now had a requirement to see if everyone had followed instructions and subscribed to the Company Announcements feed. But how to do that?

It is actually trivially easy to check. Open Site Settings for the relevant page. Then click on User alerts.

SharePoint alerts

From this page you can click on the drop down box to see who has set up an alert for this page.