Understanding Activity Dialog

HI Sandeep

Thanks for providing some very well presented documentation.  I've been
looking at activity dialog.

http://activitydialog.org/

[[

A method to open an Activity Dialog, a resource that the user controls,
that allows them to create an activity stream entry on their website, the
object of which can be any URI addressable resource. This could be
implemented as a simple bookmarklet that prefills the object of the
activity with the current URL and/or the selected text as content.

The activity stream entry should trigger an Activity Pingback to the object
and a PubSubHubbub push for followers.
]]


I'm not 100% sure I've grasped the whole concept.  Would it be possible to
give an example or describe the user experience in a little more detail?