Twitter’s new rules are restricting software developers from creating Twitter apps.
These new rules allow users log in through officially sanctioned authentic Twitter programs. There will be no access for the third party services. Software developers creating new apps will only be allowed to get a maximum of 100,000 users. Existing apps having more than 100,000 users should double their user base before Twitter imposes a hard cap. For more details read Twitter’s report – Changes coming in Version 1.1 of the Twitter API