支持不叫支持叫－ 顶
zhi chi bu jiao zhi chi jiao - ding
This is a very interesting phenomenon.
论坛里的帖子按最后回复的顺序排列，新回复一个帖子就会被顶到最前面，所以叫做“顶”。既然“顶”了就是表示给予支持.
顶 means top or apex. However, in online scenarios, it can often mean 'support'. This is because in Chinese forums, whenever there is a new reply to some other answer, the reply will appear ontop of the previous thread or reply. Therefore, it is 'on-top' which is also why it is a sign of support.
So if the netizen really likes an answer, instead of saying anything, they will just reply with: 顶!