I don't think Twitter has anything against scraping lists of followers of public accounts -- after all, that's available to everyone. (One exception I think is

I don't think Twitter has anything against scraping lists of followers of public accounts -- after all, that's available to everyone. (One exception I think is geolocation data which can't be stored.) It's then using that information to spam Twitter itself that's the problem. Facebook, OTOH, has pretty much turned off access to the friends graph for apps other than games.