1. A method comprising: receiving, at a server, a message comprising a subject, a first sentence and a second sentence; processing the message to yield a processed subject based on the subject, a processed first sentence based on the first sentence, and a processed second sentence based on the second sentence, wherein processing the message comprises identifying words in the message that are of a predefined word type; and selecting exactly one of the first sentence or the second sentence as a summary text, which summarizes the message, based on: (i) a first number of words of the predefined word type in the processed first sentence; (ii) a second number of words of the predefined word type in the processed second sentence; (iii) first overlapping words, of the predefined word type, occurring both in the processed subject and the processed first sentence; and (iv) second overlapping words, of the predefined word type, occurring both in the processed subject and the processed second sentence.