Twitter has changed the way third party applications are allowed to tweet. Starting 31 August, applications must use “OAuth” to access twitter accounts. OAuth is an open standard authentication system (IETF RFC 5849) that enables applications to access Twitter on behalf of account holders with without asking directly for the account holder’s password.

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The move should reduce the amount of Spam passing through Twitter because it makes it harder for unauthorized software to hijack legitimate Twitter applications.

For example, under OAuth, applications no longer use the account password. This also means people using Twitter applications can change their password without affecting their applications. According to Twitter, “Desktop and mobile applications may still ask for your password once, but after that request, they must use OAuth to access your timeline or allow you to tweet.” So if an account holder changes their password, their Twitter applications will continue to work.

Account holders can view a list of authorized applications on the Twitter settings web page. However, the change means existing applications that do not support OAuth must be updated if they are to continue to work. “Some applications you have been using may require you to reauthorize them or may stop functioning at the time of this change,” said Twitter in an email to developers.