Know-How Exchange : E-Marketing

More and more, the reputation of the sender AND the engagement of the audience play a greater role in e-mail delivery than spam filter scores alone (such as html to image ratios). Companies that have whitelisting programs (mentioned previous by Jay Hamilton-Roth), engage in paid certification from Return Path or similar vendor programs, and use e-mail services with aged and established IP blocks (Silverpop, etc), usually have an easier time getting to the inbox. Spam rules shouldn't be ignored, but they alone won't guarantee inbox delivery.

Gmail and Yahoo now use subscriber engagement in addition to other flags to determine junk vs. inbox placement. Engagement in this context means that if your subscriber rarely opens your e-mail message, you'll more likely go into junk because the ISP sees that your subscriber really doesn't value your messages. The quickest way around it is to have them add your e-mail address to their address book. But that is entirely another topic and doesn't answer your primary question. In the end the bigger companies get away with more because they are probably paying-to-play to some degree or have strong ISP relationships established.