Email servers configured to perform automatic summarization of content in electronic messages are discloses herein. In one embodiment, upon receiving an email, an email server determines whether the incoming email is a templated message. In response to determining that the incoming email is not a templated message, the email server classifies one or more sentences in the email as a statement of decision, judgement, inference, or fact, cluster the classified statements into clusters, and select one or more of the clusters to automatically generate summaries of the incoming email. The email server can then insert data representing the generated summaries into the email before transmitting the email to a destination via a computer network.