Tweety links your Alexa account with your Twitter account and lets Alexa read the tweets from your own Twitter home timeline.
Say e.g.:
Alexa, ask Twee Tee for the latest news
Sage z.B.:
Alexa, frage Twee Tee was es neues gibt
The terms of Use can be found here.
The Tweety Alexa Skill ("Tweety") processes Twitter account user tokens, which the Alexa service provides to Tweety as part of every request. These tokens are used exclusively to fetch a Twitter user's home timeline and present it via an Alexa enabled device. The tokens are not used or stored otherwise and are disposed after each request.
The user data Tweety retrieves from the Twitter Service is used exclusively to present it to the same user via an Alexa enabled device. It is not shared, stored or processed otherwise.
Other use of Twitter account tokens or Twitter user data than the one described above does not happen.