I know that Openfire implements PubSub compliant to XEP-0060.
I have also seen that in my administrative console I can see the Tab PubSub with the list of nodes created.
However I cannot understand how can I create a new node and what are the use cases of PubSub in Openfire.
Can you please give me some examples on how to create nodes and on actual usages in real life?
It would be uncommon for administrators of Openfire to create Pubsub nodes. I would expect the clients of end users to do this.
Pubsub can be used for a wild variety of features: basically anything that your application wants to use a publish/subscribe feature for. This can be very simple (mimicking features of RSS-capable products), or very elaborate, to include something like a shared whiteboard.
It’s smaller brother, Personal Eventing Protocol is used for features like bookmarking, user tune broadcasting, geolocation, avatars, and so on.
So it is something related to XMPP clients. If XMPP clients implement this kind of feature, as an Admin I Just have to make sure to give permissions to add PubSub nodes to all the users who want it.
Do you know any clients that implement features that use pubSub?
It’s not that clear-cut. PubSub is a protocol extension, that can be used for any purpose that you see fit. Much of the feature will be used ‘under water’ - barely noticeable to end-users. It’s not strictly reserved for XMPP clients (but you’ll often find that it’s mostly clients that use it - but then again, aren’t all features, in the end?)
I expect that most clients will use it in one way or another, if only to store bookmarks in private PEP nodes. A client like Movim makes very elaborate use of Pubsub for its activity streams. All OMEMO-capable clients will make use of PEP.
One way of discovering usage is to look at the PEP data in Openfire’s admin console for users that are active on the server. You’re bound to see some data being stored.