Nearly 269 billion emails are sent each day, according to a study by The Radicati Group. That breaks down to 2.4 million emails per second. The average office worker receives 121 emails a day and sends around 40.

That’s a lot of spam.

With the rise of instant messaging platforms and social media, a common theory was that email was going to decline. Instead, the amount of email sent daily is expected to grow by 4.4 percent through 2021.

The reason email is growing in popularity is that it remains effective. Studies by emailstatcenter.com show that businesses typically make $44 for every $1 spent on an email marketing campaign.

When the 1 Million Cups chapter in Rockford agreed to move to Thinker, the first thing we began doing was collecting cards from people who attended or who showed interest at other networking events for a weekly email. We include the upcoming speakers and links to other networking events to help our attendees find more ways to get the word about themselves and their businesses. In this case, we weren’t selling; we were trying to get people to show up. In some respects, that’s harder. Money many times is more easily given than time.

The top email marketing programs are Mailchimp and Constant Contact. We prefer Mailchimp, but both do an excellent job of making designing email campaigns easy and, just as importantly, tracking effectiveness.

If you’ve mastered one of these two programs and are looking at the data, you often wonder what is the difference between emails. Why are some read more than others? There are a number of good blog posts about the key to having a good subject line. Campaignmonitor.com says you should follow eight formulas to raise open rates:

  1. The question subject line
  2. The ‘how to’ subject line
  3. The scarcity subject line
  4. The announcement subject line
  5. The number subject line
  6. The curiosity gap subject line
  7. The surprise subject line
  8. The personalized subject line

A bigger reason, perhaps, is the day and time you sent the email. There have been lots of studies on when you should schedule that blast for maximum effectiveness. Coschedule.com aggregated many of the better studies and found that there’s no absolute consensus, but there are some good indicators. Coschedule looked at data from Mailchip, Customer.io, GetResponse, WordStream, Experian, CampaignMonitor, HubSpot and MailerMailer.

When is the best day to send an email?

In general, if you’re sending out just one email, Tuesday is clearly the best day to send it. This makes a lot of sense. Monday is usually spent cleaning out email and preparing for the workweek. People just aren’t into reading as much. On Friday, people are trying to clear out of the office for the weekend. Who wants to read emails when you’re trying to shut down?

Thursday is the second-best day to schedule an email, followed by Wednesday.

One interesting thing to note and perhaps to test is that many studies found clickthrough rates increase on Saturdays and Sundays. People actually open far fewer emails on the weekends, but the people who do are invested in what they are reading.

When is the best time to send an email?

There’s an interesting result in this data. The best time, according to several of the studies, is 10 or 11 a.m. That gives people an hour or so to get settled and it’s before lunch. The next best time is 8 p.m. to midnight. Campaign Monitor noted that this is because of our natural inclination to check email before bedtime. The third best time is 2 p.m., when people look for distractions. The final best time is 6 a.m. to catch the people who check email as soon as they get up.

Of course, all audiences vary. The best thing about modern technology is the ability to A/B test. If you’re doing something monthly (or weekly, in the case of 1 Million Cups), alter days, times and subject lines and compare the results. Chances are it’s not just chance.