It actually doesn't seem so bad on looking at it. It seems like they just want to use your tweet in some kind of collage or something and they were trying to cover their bases by claiming the right to do so.
I think it would've been better to say "If you use this hashtag we may retweet you or feature your comment in promotional material" rather than asserting that you would agree to something by using a hashtag.
Yeah, except that I don't think they are allowed to feature your comment in promotional material without consent (tweets aren't public domain to the best of my knowledge). Same way you can't just reuse a Star Wars trailer in your own promotional material.
> B. License from Twitter. Subject to the terms and conditions in this Agreement and the Developer Policy (as a condition to the grant below), Twitter hereby grants you and you accept a non-exclusive, royalty free, non-transferable, non-sublicensable, revocable license solely to:
> 1. Use the Twitter API to integrate Twitter Content into your Services or conduct analysis of such Twitter Content;
> 2. Copy a reasonable amount of and display the Twitter Content on and through your Services to End Users, as permitted by this Agreement;
Point 2, you licensed the content to twitter and they license it via the developer portal.
I think it would've been better to say "If you use this hashtag we may retweet you or feature your comment in promotional material" rather than asserting that you would agree to something by using a hashtag.