I'm building a set of plugins... obviously, being plugins, they need to be suitable to a variety of installations. These plugins will keep track of specific types of user activity (namely whether links are clicked, actions taken, petitions sighned, that sort of thing) and provide access to the resulting data to the administrator.
So my question is custom post types vs a specific set of bespoke database tables... I would normally choose custom post types for this kind of data, but a succesfull campaign could result in 10,000s, even, if really successful, 100,000s of actions being recorded. Since the objective of the plugins is to assist people in developing succesful campaigns this is obviously the kind of scale I need to think about, so I am concerned about the possible degredation of wordpress performance if the wp_posts table is are swamped with 10,000s of custom post type entries. Is this a case where I would be justified in creating a new set of database tables to handle my data?