Occasionally people will respond with this emote to some of your more precariously aimed remarks.
Is translated to and can be interpreted as a thanking; thank you.
More Ts can be added by the other person to extend or increase the amount of thanking that you receive.
Replying with "yw" is perfectly appropriate.
Tom: you look like a girl lel
Some retard: thats not what T_T means
Tom: /meh/, yw