Last spring an announcement from the platform team at Twitter not-at-all-subtly suggested developers of third party clients should find something else to do, and today a list of changes to its API turns that whisper into a firm nudge. The limit that most directly affects any of the unofficial clients you may be interested in using is that existing apps currently servicing more than 100,000 individual user tokens will be allowed to double their current count, but cannot add any users past that without Twitter's permission. Going forward, any app that needs more than 100,000 tokens to do things like access the timeline, show DMs or anything else a client app might do will also need Twitter's permission to operate. Other changes include that any pre-installed client app on something like a phone, computer, or TV will need Twitter's permission before it ships (sensing a trend here?), or potentially face revocation of its application key. Moving on, the Display Guidelines about the information any app that displays tweets must provide are shifting to Display Requirements, with violators potentially losing that application key. Those Twitter Cards that started rolling out over the last few months are also getting a big push, with plans to include other ways for developers to bring their rich content to Twitter, and embed real-time Twitter content on existing websites.