What is the "impersonal si" and does it translate into "yes" in English?

Most of the time and in most cases the word "si" translates into "yes" in English, but sometimes Italian people use the same word to mean something completely different, i.e. an impersonal pronoun. Before starting, let's refresh your mind with what a personal pronoun is: personal pronouns are pronouns, or parts of the speech, that refer to a particular grammatical person. There are two categories: singular and plural. First singular person is "I" (io), second singular person is "you" (tu) and third singular person(s) is "he/she/it" (egli/ella, esso/essa, lui/lei). First plural person is "we" (noi), second singular person is "you"(voi) and third singular person is "they" (essi/esse, loro). So, personal pronouns express who or what took part to the action of the sentence. The impersonal pronoun acts in a similar way, such as that it grammatically expresses the subject of the action. However, contrary to personal pronouns, it does not give information regarding the subject that takes part to the action in the sentence. In English it translates into the passive form, such as "Di solito in Italia si mangia tanta pizza" = "In Italy a lot of pizza is usually eaten". "Si" can be substituted with "la gente" (people), "qualcuno" (someone) or even "one" (a person). Another example can be "Si dice che domani pioverà" = "It is said that tomorrow will rain"; We don't know or don't want to say WHO said WHAT will happen tomorrow, or even we are unsure about the reliability so we use the impersonal form "si". So, in a way, the impersonal pronoun "si" is used when a distinction among people is not needed or information regarding the subject or agent are not provided