Friends Don’t Let Friends Invite Spam Traps
One popular list growth tactic for email marketers is the invite-a-friend functionality. If you aren't currently using it, you're probably familiar with it. Everyone from social networks to flash-sale sites use it to grow their subscriber base by allowing subscribers to log into their webmail account, upload their entire address book and send an invitation email asking their friends to join. Its ability to go viral makes it extremely effective. It does come with risks, however. Without proper measures in place, invite-a-friend can destroy your email deliverability.
My company's latest reputation research study shows just how risky invite-a-friend functionality can be. We looked at the most common reputation measures across 130 billion IP addresses and trillions of messages. The measures we focused on included the following:
- Complaints: the rate of which subscribers reported email messages as spam. Internet service providers like to see this number under .1 percent.
- Spam traps: decoy accounts sent up to catch spammers. The only acceptable number is zero.
- Unknown users: email addresses that don't exist. Good mailers have an unknown user rate of less than 2 percent.
There was one industry that stood out like a sore thumb for its poor performance: social networks. Not only were social networks’ 3 percent average complaint rate and 5 percent unknown user rate the highest rates of any industry, they also had by far the highest number of spam traps. Most industries had average spam trap rates of less than two per IP address, but social networks had an average of 20.8 per IP address. The culprit: invite-a-friend functionality.
The reason for the high number of spam traps and unknown users is address books not being updated. Most people, myself included, never update their address book or clean out old email addresses. A large portion of addresses are abandoned, thus qualifying them as an "unknown user." ISPs like Hotmail, for example, often create spam traps out of these old, abandoned email addresses. Chances are you probably have some of these recycled spam traps in your own address book without knowing it.
There are a number of ways that you can still use invite-a-friend without destroying your reputation. Try the following:
- Limit your invites. The more addresses a subscriber uploads, the greater chance of mailing to unknown users or spam traps. By limiting the number of addresses a user can upload, subscribers are more likely to choose only recent, valid email addresses.
- Choose an appropriate frequency. Some businesses will continue sending to uploaded addresses until the email address joins or unsubscribes. Limit your invitation frequency to two invites at most — the initial invitation and then a reminder within a week. If the subscriber doesn't respond, don't email them again. Ever.
- Don't allow custom messages. If you do, put restrictions in place. Never allow HTML or links in the message, as these can be used by spammers.
- Make the invitation recognizable. While I don't recommend spoofing your From domain to look like it was sent from the inviter, you can still use the subject line to inform recipients who invited them. This helps reduce complaints and increase open rates.
- Use a global unsubscribe. Some people never want to receive an invitation, and can be irritated to receive multiple invites from multiple friends. Allow these recipients to opt out from all future invites.
Do you currently use this list growth tactic? What problems have you experienced, and how did you solve them? Let me know by posting a comment below.