Effectiveness: Very Low

Advantages: Bounce is one of the only methods that can actually lower the physical amount of spam you receive. (However there is an equal chance it can increase the level of spam you receive.)

How does it work:  When a message is bounced spammers who receive a bounce may remove your email address from their spam lists.  It is most effective against the semi-legitimate spammers who use real email addresses or domain names which will be more likely to receive a bounce message.  This feature is no longer considered an effective strategy against stopping spam in many cases.  The main reason is because most spammers use disposable email addresses and hacked machines.  So they will never receive the bounce.The bounce you send a spammer may bounce right back to you.

Limitations: Bouncing all your messages is labor intensive, it requires you to review and bounce the spam messages you receive.  It is ineffective against many spammers as they do not use legitimate return email addresses, so they will never receive the bounces and they may bounce right back to you.  It also uses extra bandwidth to send and retrieve the bounce messages.  Another problem is many of the messages you bounce will be returned to you if the email address the spammer uses is invalid or no longer active.  This could give the appearance that you are receiving more spam when actually you are just getting back the bounce message you sent from SpamBully.

Recommendations:  Bouncing is most effective for users with very light amounts of spam messages.  If you receive 5-10 spam messages or less a day, this may be an effective part of your spam solution provided you review each message to determine whether the user is likely to receive the bounce.  For higher levels of spam, generally the effort required to bounce every message is not worth the few lists you may be removed from.  It is more effective to concentrate your efforts on keeping your Bayesian spam filters properly trained.  If you feel you want to get back at spammers, use the report as spam option in message details.  This sends a letter of complaint to the FTC, the spammers ISP and advertisers to hopefully get them banned or investigated.  This may hurt a spammer far more than bouncing a message.