No bird site did not change T&C, it only got noticed. Always been that way. The reason for those T&C is to allow legal embedding of tweets in other media and even to allow retweeting at all. Such a T&C is necessary for any site that allows embedding/reposting of anything other than public domain/CC content.
Nonetheless, ppl should realize images, etc can get re-tweeted, reused by others on social media. If you don't want that, don't share on social media.
@econproph I’m reasonably careful about what I tweet these days anyway. I don’t put anything up that I wouldn’t want the world to see. I was thinking more about perhaps artists that tweet their original work, and how the ownership maybe be affected under the T&C (which although not new, are effectively new if people are only realising now....I’m not the only one that is just becoming aware of it).