Email marketing’s ROI is twice as much as direct mail and three times as much as social media. So why are we not investing in growing our email lists in the same way we do with these other channels? I am not referring to buying lists like we do for direct mail. They certainly are available for email, but even if we put aside the massive deliverability issues that accompany purchased lists (recipients who have not heard of you are likely to mark messages from you as spam, making it harder for your messages to reach the subscribers who are genuinely interested in hearing from you) there is a fundamental problem with the ROI of rented lists. Not only does purchasing lists increase the Investment, but mailing to people who have not shown a previous interest in your brand by subscribing through some channel depresses the Return. You simply cannot buy lists and expect the ROI of email marketing to remain high.

But what if instead of buying email lists, we invest instead in methods designed to encourage more people to willfully subscribe? That is exactly the model that Facebook has come up with, making it very easy for brands on its service to advertise to members expressly to grow their fan base. If your brand has an attractive value proposition, putting it in front of as many targeted prospects as possible makes sense. So yes, you can advertise to grow your email list, the same as you might advertise to sell a product. The only difference is that the ask is less, which should translate into a higher conversion rate for your ads.

Advertising to for subscribers is not a common practice yet, but it should be. Here’s how to do it:

Choosing Media:
There are very few advertising campaigns for which Google Ad Words and Facebook Ads are not a good choice, or at least a starting point. Both have intuitive ad creation and purchase flows, offer ample targeting based on keywords or interests, and are easy to modify as your campaign runs. Best of all, the buy-in price is virtually $0 and both services allow you to set a daily budget. This makes it easy to learn what works and what doesn’t before committing to a larger buy. Facebook also allows for display advertising, which is worth testing if you are looking at specific sites for which your brand is well suited that do not carry text ads. LinkedIn is another candidate for an initial buy. Its setup interface is similar to Facebook’s but the minimum buy-in is higher, at $10/day.

Writing Ad Copy:
The media choices above all allow for pay-for-performance ads. The upside to this model is that if nobody clicks you don’t pay. But the downside is that ads that don’t perform well end up being less profitable for the sites so they run them less frequently or even pull them for poor performance. Ad copy that reads “Sign Up For Our Big Data Integration Newsletter!” ends up being well-targeted since nobody not interested in the newsletter would bother to sign up. But it may not perform well since it does not also offer much insight into how specifically the newsletter will be valuable. The other end of the spectrum might be an ad that promotes “Free Big Data Conference Registration,” and then uses the landing page to inform prospects that someone who signs up for email will win a drawing for the free attendance. This ad will pull a ton of clicks from people interested in big data and going to a conference for free, but they may not end up being the most engaged newsletter subscribers, particularly after 99.x% of them learn that they didn’t win the trip to the show. Find some middle ground that promotes how the newsletter adds value to an interested audience, like “Sign up for the Big Data newsletter your competitors read” or “Breaking news on Big Data delivered daily.”

Remaining topical:
Text ads in particular are very easy to keep fresh and topical. If your newsletters are really good enough to advertise, use your best content in your ads, in near-real-time. “New Tips Every Week” might be an ad you keep in rotation, but try also telegraphing specific copy in upcoming newsletters, like “The Secret to 2x ROI on Thursday – subscribe today.” Pre-promoting compelling content can not only accelerate subscriber growth, but also provide you with an opportunity to meet their anticipation with the very first newsletter they receive, helping to engage them right from the start.

Tracking and Evaluation:
Make sure you put all your externally acquired subscribers into their own group, or into separate groups for each site they came from. This allows you to track their engagement against subscribers who found your list through your current channels. Because you are paying for these new subscribers, making sure they respond to your newsletters strongly enough to justify the expense of acquiring them is critical, as is making sure you are spending money strategically. If your Google subscribers are twice as productive as those you acquired on LinkedIn, shift budget to where it does the most good.