With many social networks such as Google+ and Pinterest now supporting GIFs, Twitter has joined in too.
Twitter announced via their Twitter Support account that from today users will be able to share GIFs in tweets. However they will not be auto-playing. It will require a click on the GIF for it to start playing.
Currently it only works on the desktop site and Android and iPhone apps.
This should make tweets a lot more interactive and interesting, especially considering they're very popular on sites such as Google+ and Tumblr.
— Twitter Support (@Support) June 18, 2014