Email marketing remains the workhorse of many brand campaigns. Not as sexy as Instagram or slick as Facebook, email remains a key way for brands to communicate with customers.

Here's a look at how email marketing looks in 2015. 

You've Got Mail

According the MailChimp, email open rates varies greatly between industries and interest groups.

Users in the Arts and Artists and Hobbies categories are most receptive, with 29.93% and 28.35% open rates respectively. 

Email marketing campaigns covering Daily Deals, eCommerce and Pharmaceuticals are least likely to be opened.

Half of recipients make at least one purchase annually based on an email promotion.

Subject line

Spamalot

Email marketing still faces a spam problem.

Close to three quarters of users will determine if an email is spam based on the subject line, while 21% will mark an email as spam even if they know it isn't.

Shifting sands

Having an email database means constant vigilance.

Some 17% of US internet users create a new password every six months, while one third of subscribers change their email address annually.

Bigger is better

The bigger the company, the more likely the open rate. Companies with over 50 employees see average open rates of 24.13%, compared to 21.60% for companies with between 11 – 25 employees.