Option to add the page to the watchlist of the recipients when sharing a page by mail

This option would be useful when you want to draw the attention of some of your coworkers on a particular page so they can start watching it and be notified by changes.

On the UI side, it could be as easy as a simple checkbox inside the share page form.

There should also be some form of authorization involved, since not everybody should be allowed to push pages to your watchlist.

On suggestion would be to integrate it with the list of watched users, since you are already interested in their activity, so it would make sense to allow them to push documents in your watchlist. If somebody is abusing this authorization, just stop following/watching the person and clean your watchlist (to undo any possible spam sources).