What kind of petition is it? From my understanding most petitions need to be verified in some fashion. If it is merely a petition to an official and not subject to some legal requirement, e.g. to run for office you may need a certain amount of signatures to make the ballot in a district, then it shouldn't matter. Most don't lend much credence to online petitions, especially those that have no measures in place to ensure that there aren't multiple entries by the same person. People can get in trouble for forging someone else's identity.