Twitter is all about making their Twitter and Vine services more human, apparently. No long will we show how much we like a Tweet or Vine with a mere star. No, starting today, we'll demonstrate our love with that romantic of symbols, the heart.
— Twitter (@Twitter) November 3, 2015
Twitter has updated their apps accordingly, although third-party apps might take a little time to catch up. The Windows 10 Twitter client is fully on board, as you can see.
The same thing with the Windows Phone/Windows 10 Mobile Vine client:
So, if you'd rather show your heart on your sleeve, Twitter has you covered. Download the apps and put your heart out there.