I believe the new way to do this is to initially call the REST API to get all of the ids for the first time you process this user. Then you setup a User Stream on the user and process any requests that come in through there. For your uses, if you only show users the differences in follower counts then you don't need the initial call to the REST API to collect all ids. All you need is a count of the ids and then to initiate a User Stream. The User Stream will give you the differences in real time and you can store just the differences, instead of the entire set of ids.
David Giamanco -- Twitter developer documentation and resources: http://dev.twitter.com/doc API updates via Twitter: http://twitter.com/twitterapi Issues/Enhancements Tracker: http://code.google.com/p/twitter-api/issues/list Change your membership to this group: http://groups.google.com/group/twitter-development-talk