I’m glad to hear your interest, Mario. There might be too much to fit in a reasonable reply here! My first suggestion are the examples and rationale shared from Hypothes.is itself
The plugin part you speak of is more about educators who wish to automatically make their materials annotation ready, and it comes built in with any OER published on a Pressbooks platform. An example I found recently was by David Buck at Howard College, where he has activities for English Composition students to listen to TED Talks about the UN SDGs and asks them to annotate the transcript, e.g.
But you do not need to host content to create annotation activities. You can create activities, assignments where you ask students to annotate any public web page.
Try this, if you visit the web page with OE Global’s history– it’s just a web page. But install the extension or bookmarklet to your browser, and the notes/conversations become available.
It becomes an extra layer of information on the entire web.
Yes, you can create groups to have annotations only available to a class. In my use, I found this a bit cumbersome, as it requires all participants to remember o flip the interface control to use the group. And I think it makes for more potential open pedagogy to engage in public conversations.
Annotations can be tagged, say with a course tag, or assignment tag, so you can pull notes form multiple sources into one view. I used this for a few different iterations of a course https://hypothes.is/search?q=tag%3Anetnarr
Another aspect that is useful is that your Hypothes.is username becomes your activity archive- so you can find links to everywhere you have annotated (the highlight tool becomes useful as well) https://hypothes.is/users/cogdog?q=