The development version of the Add Link to Facebook plugin supports bbPress now.
For new bbPress topics links will be added to Facebook. bbPress replies will be sent to Facebook as comments (option) and comments on Facebook will be imported as bbPress replies (option). It is also possible to use the social plugins on bbPress, notably the like button.
To add links for all users, including anonymous users, the option ‘Share with all users on this site‘ should to be enabled.
Reports, good or bad, are very welcome.