You can see the Alert Me button is enabled. But when you try to create one for yourself, you will be surprised to see following message.
What? The site hasn't been shared with you? If the site has not been shared with you, then how can you view the library and view item? Well, I tried to do the same thing in my SharePoint 2010 environment. And it did allowed me to create an alert for Read Only user without any hassle. You may wonder if there is something wrong with SharePoint 2013 as I did. After doing some hit and trials with User Permissions, I was able to figure it out.
Lets go this way.
- Login to the site with another user with higher privilege, i.e. Site Owner.
- Go to Site Settings.
- Go to Site Permissions.
- Click Permission Levels on the ribbon.
- Click the Read Link.
- Check Browse User Information and Submit. Now, log in back to your site with previous read only users. If you are using separate browsers for two uses, refresh the browser. You should be able to create your alert without any hassle.