At the same time, social media, online marketing and advertising, along with search engine optimization (SEO), developed additional means of marketing, which some people thought were more effective. Businesses were all looking for that guaranteed channel to success. Spoiler alert: It doesn't exist!

Mobile application

When you added into the mix the footprint of mobile, everything I mentioned previously took on a whole new feel. Online ads, social media and email marketing all had to rethink their approach. When native apps for iPhone and Android were included, the choice for the best online marketing approach became almost impossible.

Some businesses pulled away from email to focus on websites and a robust search engine opitimization (SEO) and social media strategy. Still others focused much more on mobile apps. But email continued to evolve and succeed. Because of these changes in message delivery, effective emails are shorter and linked to video content or social media posts and blogs. It's the way we reuse content to get the most out of the message. If you have a regular blog, using social media to alert your followers to a new post is one way to spread the message.

Opening the email door

Email has an average 30 percent to 40 percent open rate, which can go up or down depending on the quality of the mailing list. Much of its success depends on the subject line attached to it, however.

Here's where it gets complicated. Understanding the psychology of consumers and what will get someone to open an email requires a Ph.D. Some studies point to certain words as more effective than others. Still other studies say short, simple subject lines work best.

We've all heard that subject lines that refer to the “top 3” this or the “Worst mistake” of that, claim to have high open rates. But the recent negative reports on “clickbait” headlines have carried over to email subject lines with spam systems automatically pushing them into junk/spam folders.

Getting the subject line right is critical, as is the “From” email address. Some addresses trigger other systems to identify emails as marketing or newsletters taking them out of the mainstream inbox your recipient regularly sees.

Navigating your way through these email minefields isn't easy but it is worth the effort. Systems like Constant Contact, MailChimp and iResponse, for example, offer a variety of resources that can help you choose the right subject lines, best time of day to send and the template that best matches the conduit throughout which it will be received.

But there are no e-mail marketing platforms that can make up for having the wrong message, not sending it to the right audience and not listening to the response you get.

Finding the right technology to support your engagement efforts is the best combination to reaching the marketing success you're after.

Rick Gilman, APR, CMP, is president of APPsolute Marketing, a communications and public relations consulting business specializing in mobile marketing and APP development for small business. Contact him at [email protected]. Opinions expressed in this article are the author's own.