Thanks for the feedback. I will try to answer some of your points.

• This in not an API to replace the old subscriptions feature, bad naming from our part. It is just a very raw API to deal with notifications and storing subscriptions to arbitrary keys. We will update the SDK.
• You are not supposed to call the provider directly, you just call INotifier and implement your own formatter, see code examples. The dispatcher scheduled job takes the messages and call the formatter and then passes on the formatted message to the provider. So ProviderNotificationMessage is only created by the dispatcher and not by any code using this feature.
• Messages are not removed, they are just marked as sent so they can be queried from an UI. For example projects will show notifications in the UI in an upcoming versions. A scheduled jobs cleans the table (after 3 months or something).
• A lot of logging exist if you don't think it behaves as it is supposed to, for example when it cannot find a matching provider etc etc. Especially the class EPiServer.Notification.DefaultNotificationDispatcher, enable debug logging for that class in your episerverlog.config.
• Implementations are often internal and abstractions/interfaces are public, that is so that we can make changes to the implementations without forcing us into a CMS 10, or 11. Is there anything internal that should be public let us now and what you need to use it for. I logged a bug for ProviderNotificationMessage even though you would only deal with that class if you implemented your own provider (if you are not using e-mail).

Thanks for the answer, I'll look into it and see if I get it to work now :)

Per,

Thanks for the debugging tip. The reason the notification didn't work was because it couldn't find any formatter ->

2016-01-28 10:14:52,664 [78] WARN EPiServer.Notification.DefaultNotificationDispatcher: No Formatter found for Channel("epi.example")
2016-01-28 10:14:52,678 [78] WARN EPiServer.Notification.DefaultNotificationDispatcher: No Formatter found for Channel("Andreas kanal")

I added a formatter and it sent an email.

You should change this 

var notificationRepository = ServiceLocator.Current.GetInstance<INotificationRepository>();
INotificationUser receiver;
INotificationUser sender;
 
await notifier.PostNotificationAsync(new NotificationMessage()
{
        ChannelName = "epi.example",
        Content = "A page has been improved!",
        Subject = "Improvement",
        Recipients = new[] { receiver },
        Sender sender,
        TypeName = "PageChanged"
});

to

var notifier = ServiceLocator.Current.GetInstance<INotifier>();
INotificationUser receiver;
INotificationUser sender;
 
await notifier.PostNotificationAsync(new NotificationMessage()
{
        ChannelName = "epi.example",
        Content = "A page has been improved!",
        Subject = "Improvement",
        Recipients = new[] { receiver },
        Sender sender,
        TypeName = "PageChanged"
});

in this guide -> http://world.episerver.com/documentation/Items/Developers-Guide/Episerver-CMS/9/notifications/code-examples/

Thanks for the help!

<pre class="brush:html;auto-links:false;toolbar:false" contenteditable="false">Hi, I am new to EpiServer 9.. My new requirement is to create email subscription module. When users subscribes to the blog, all the subscribed users should receive email if any updates happens to that blog. I have no idea on how to proceed further .Can you please share all the steps to build the email subscription module ? If possible, can you please also share some working code ?</pre> <p></p>