Exactly, Kyle. I would like a video explaining how to use notifications in CB Activity in the current stage (with triggers of CB Auto Actions).
Or is it better to wait for a CB Activity 5.0 to use on a production site?
Any activity generated with the asset prefixed with "notification.USER_ID" with the USER_ID being the user receiving the notification will be treated as a notification. That's basically all there is to it. However there are no notifications from system, which will be coming in CB Activity 5.0.0 (basically a notification from the site and not any specific user). You can use this now to generate notifications, but it's going to be a lot easier with 5.0.0 and a lot more database efficient since the notification prefix causes mixed content (activity and notifications in the same database table).
Also. I still do not know how to use this feature ( is it with CB Activity module ?).
It's a new trigger. Specifically activity_onAfterCreateStreamComment. The variables are as follows.
$_PLUGINS->trigger( 'activity_onAfterCreateStreamComment', array( $stream, $source, $row ) );
This means var1 is the comment stream object. var2 is the comment source (what is being commented on). var3 is the actual comment object. So if you wanted to set an email to the activity owner when someone comments on it you'd set the To value for the email action to [var2_user_id] and the From value to [var3_user_id].
I would like a video explaining how to use it.
A video isn't going to really help you with either use case. They're too advanced and too subjective to their context. A text based tutorial would be a better approach for something like this, but that's up to Nick if he'd still like to do a video for this functionality. My recommendation is wait for CB Activity 5.0.0 where I'll have system actions implemented in CB Auto Actions to handle notifications, which would at least make it easier to explain in a video since there will be several examples available.
After this release, we had important and very useful features implemented with CB Activity 4.0 ( www.joomlapolis.com/news/18725-cb-activity-4-0-released-along-with-3-more-supporting-add-ons ) which I think are worth a new series of videos.
A new video regarding uploading from CB Activity powered by CB Gallery would be great.