Twitter's new terms and conditions, and its overall attitude, are tougher on developers who work to fill in holes in its infrastructure. This is the risk of putting your effort into a platform controlled by a single company.

Twitter has told developers in simple and straightforward terms to stop building apps that present the Twitter consumer experience.

Developers have told us that they’d like more guidance from us about the best opportunities to build on Twitter.  More specifically, developers ask us if they should build client apps that mimic or reproduce the mainstream  Twitter consumer client experience.  

The answer is no.

What this means is that you are no longer welcome to create Twitter clients, even if they run on currently unsupported platforms and if you have already expended the energy doing so - tough.Twitter recently suspended three existing mobile clients owned by UberMedia, but they were reinstated after some changes and being renamed.

The announcement was made on the official developer mailing list and the reason given was to increase the consistency of the user experience.

Twitter will provide the primary mainstream consumer client experience on phones, computers, and other devices by which millions of people access Twitter content (tweets, trends, profiles, etc.), and send tweets.

Essentially it looks as if Twitter had been more than happy to have help with software development to spread its service to new platforms and situations but now it wants the market to itself.

In addition the terms of use of the API are being changed to prevent apps from displaying data obtained from other services alongside data obtain from Twitter or from capturing and redistributing Twitter content - even for research purposes.

It seems likely that in time Twitter will move to take over additional ways of presenting and using its data so as to maximise its revenue.  However it still has the promise that, when it starts to include advertising via its API, it will share a portion of advertising revenue with apps that accept the ads.

To put it bluntly Twitter is in control of its API and the data that its users create. The harsh lesson to be learned from this unwelcome news is that there are risks involved in creating software for a platform that is controlled by a single company.

More Information

Twitter Google Group announcement

http://dev.twitter.com/pages/api_terms.

Twitter outlines developer plans