Radioactivity does not work well with page cache and anonymous users

Radioactivity does not work well with page cache and anonymous users. This is because radioactivity_user_node_view($nid) is called from nodeapi. It does not get called when the page is retrieved from the page cache, and thus, the energy does not get increased. Better would be to call radioactivity_user_node_view($nid) from radioactivity_exit, which is always called (see statistics module).