Recipients glance at each subject line for only a couple seconds before deciding whether or not to open an email. Needless to say, the subject line is a critical part of each message. MailerMailer analyzed the subject lines of more than 1.2 billion messages to identify subject line trends. According to our findings, relevant and persuasive words are frequently chosen to craft subject lines. Additionally, brief subject lines entice the highest open rate, while moderately long subject lines are associated with the highest click rate.
The top 100 words used by our customers are represented in the tag cloud below wherein size and shade of each word correlate with frequency of use. According to our results, words such as news, free, tonight, party and sale reigned as the most popular choices. Other popular choices include newsletter, night, and weekend.
These choices indicate that customers strive to make their subject lines relevant (news, newsletter) and persuasive (free, party, sale), as well as emphasize time sensitivity of the message (night, weekend).
How to find the right keywords to ensure you are using words that will resonate with your readers try using Google Keyword Tool to research the most fitting keywords for your content.
Like last year, short subject lines, specifically with less than 15 characters, boasted the highest open rate (15.2%). The longest subject lines, containing over 51 characters, resulted in the lowest open rate of 10.4%.Unlike last year’s data, the trend between 16 and 50 characters is weak, showing neither a steady decline nor increase.
Click rates plotted over subject line length resulted in a normal distribution, similar to last year’s findings. The highest click rates were experienced by emails with 28 to 39 characters in the subject line. Rates decline as one approaches shorter or longer subject lines.
Without further data, the relationship between these metrics remains in speculation.
http://www.mailermailer.com/resources/metrics/2012/subject-lines.rwp July 2012 Edition