Watch list allows users to keep track of items they are interested in.
You need to adjust the menu item parameter "allow watchlist" to turn on the watch list feature, it's turned off by default. You should also set this in your component options.
Each item has a "add to watch list" button
Which adds the item to their watch list view (you need to add new menu item for watch list)
The delete button removes the item from their watch list.