So what the subject is, okay, so if it's something like, you know, buy such and such, a whole bunch of spam.

那么这个主题是，对，如果邮件是，很多关于购物的垃圾邮件。

哈佛公开课 - 计算机科学课程节选

We look at what emails you reply to if you reply in theory that suggests this user must care about whoever sent this email or the topic they are in.

我们看看哪些邮件要回复,如果你回复了,理论上来说这表明了用户一定很关心,发件人以及邮件的主题。

哈佛公开课 - 计算机科学课程节选