ClickZ: Critical Questions to Ask Before Renting a List

Here's a good reference article that provides a list of consideration points when renting an e-mail list. So, check this before you rent:

• How and where is permission collected? Are lists opt-in?

• How often do individuals on the list receive offers?
• Are new names added regularly? Are unsubscribes removed promptly?
• Is the list exclusive to this manager?
• What does the sender line look like?
• How does the list manager ensure proper message delivery? What's the average undeliverable rate?

Check the article for more enlightening tidbits.