We've added a new piece of text to the footer of blast emails (the emails sent from petition creators to their supporters). Now, in addition the required unsubscribe text, you can also ask people who have signed petitions on your site to start their own. the new text is included right above the unsubscribe text.
If you'd like to change the default text, or add a translation, you can do so by going to "Content" under "CMS," clicking "Petitions" and choosing "Start Campaign ask in blast email footers."
If someone starts a campaign using the start a campaign link included here, the petition will be tagged with the source code "petition_email_footer." Source codes for petitions can be viewed by going to "Hot" under "Petitions" and clicking "By Source."