4. Never agree to handle the e-mail send on your own: In the offline world, the list owner or broker provides an electronic file or labels to the renter, who handles the send. In the e-mail world, the list owner or broker doesn't provide either of these. Instead, you provide your creative to the owner or broker, who then handles the send for you.
This is done to protect the integrity of the list. It also assures that the bulk of any spam complaints or blacklisting will impact the list owner or broker—not you. If someone offers to rent or sell you a list but requires you to handle the send on your own, beware.
5. Always test when you're mailing to a new list: As with offline lists, you want to test a small portion of the list before you rent the entire universe of names. In the offline world, a test quantity is usually 5,000 names. In the e-mail world, I prefer to test at least 10,000 to get a good read on the results. Legitimate list owners and brokers will allow you to do this.
If you're just getting started, test three different lists with two creative executions (one being a control version that is successful to your house list, if possible). In my experience, this type of a three-by-two grid will usually yield at least one successful list/creative combination that you can roll out.
6. Develop performance projections: Before you test an e-mail list, run the numbers. Determine what type of response you need to break even—and what ROI you'd need to make this a "winner." If those figures are unrealistic, reconsider your list rental strategy.
7. Have realistic expectations: In my experience, an e-mail rental list will perform, at best, about half as well as a marketer's in-house e-mail list. If you don't have metrics from your own house list, then assume no more than half of e-mail industry benchmarks. According to the Epsilon Q4 2009 North America E-mail Trend Report, the following are overall averages for house e-mail lists: