One of the most useful plugin is Tell a Friend form. Usually this is an email form, which you can send to your friend with short information about something interesting in website you have just visited. Some of this plugin versions give you possibility to send email from website email service set as sender. For this reason in plugin form there is only one email address field – friend’s email address. This solution is not always perfect, especially if shared hosting email server address is very long and strange.
AF Tell a Friend Plugin has two email addresses fields: one for sender and another one for friend’s email. Essential feature used in this plugin prevents spamming: message box is set as read only, but automatically contains link to referred page.
More detailed information about this plugin can be found here: