A recent study of roughly 5 million emails identified seven deadly words: confirm, join, assistance, speaker, press, social, and invite. Recipients are less likely to respond if any of these words appear in the subject line of an email, according to the study by email plugin provider Baydin.

How often are PR and marketing professionals using these words in their subject lines?

More than 10 percent of the time, according to a new analysis by Yesmail, which makes software for tracking email and social media campaigns.

Prompted by PR Daily’s story about the seven words, Yesmail analyzed 110,000 email subject lines from the past year to determine how often these words appeared.

The advertising and marketing industry—which includes PR professionals—uses one or more of those words in 12 percent of its email subject lines, according to the analysis. The news media industry, on the other hand, uses them in only 1 percent of its subject lines.

“Social” seems to be the favorite word of the advertising/marketing industry. Among emails across all industries, the advertising/marketing industry accounted for 62 percent of the overall use of “social.”

“This isn’t a surprising discovery considering marketers are often promoting events and inviting email recipients to join social tweet-ups, guest speaker discussions, webinars and many more,” said Steven True, senior digital sales strategist at Yesmail.

The word “invite” was in heavy use in subject lines from the travel and tourism industries, department stores, magazines and publication, and Internet retailers. More than half of its use (54 percent) came from these industries.

“It is not really surprising that travel and tourism is ‘inviting’ people to take action,” True explained. “However, if marketers in that industry are more specific about the event/trip/activity they are promoting, right from the subject line, they may be able to entertain more email opens, clicks, and, ultimately, conversions.”

The word “press” is popular among PR professionals because they’re often sending press releases to journalists and bloggers. Often, the subject lines begin with, “Press release …” If this sounds familiar, you might want to reconsider that approach.

“Email recipients often tend to overlook the value of emails that advertise press releases,” True said. “If ‘press’ is in the subject line, a recipient is more likely to avoid opening the email.”

Curiously, the clothing and fashion industry and the group buying industry, which includes daily deal sites such as Groupon and LivingSocial, account for 25 percent of the total use of “press.”

A better bet than indicating “press release” in a subject line is to include the headline of the press release—assuming it’s a well-written headline, of course. And the best headlines often make irresistible subject lines.

“Ever flip through a magazine or newspaper and some crafty headline catches your eye?” PR specialist Jamie Szwiec wrote in a PR Daily story recently. “The more you see and read them, and write headlines, the better your subject line writing will be.”

When contacted by PR Daily, Mitch Delaplane, a PR professional in Chicago, echoed these remarks. He said that from the subject line to the body copy, email pitches should be creative, fun, and enjoyable to read (and, of course, jargon free). Also, less is always more, according to Delaplane.

Overall, subject lines will improve if you avoid vague language.

“To elicit a response, your email communication, starting from the subject line, needs to be specific in terms of the product or service you’re promoting and the action you’re prompting your recipients to take,” True said.