By John Alexander

When is the best time of the week to send your newsletter?

Which day of the week results in the the highest average open rate?

Sending your Newsletter at what time of day time generated the highest open rate?

All good questions, right?

If you publish a permission based newsletter using a sequential auto-responder like Aweber.com you may be interested in a few of the most recent statistics taken from thousands of AWeber customer newsletters sent over the past 30 days.

These statistics represent some interesting facts about how opt-in newsletter subscribers are absorbing your news.

This does not really relate to search engine marketing or SEO but I know a lot of our readers do use Newsletter communications to assist with a significant part of their sales conversion process.

The following facts were presented to me by Mr. Tom Kulzer the CEO & Founder of AWeber Communications.

Interesting reading! Please enjoy.

Best regards
John Alexander

Real World Statistics taken over the past 30 days as of August 10, 2005

Facts:
There were 12,561 subscribers in an average customer opt-in newsletter list on Aweber.

4 minutes and 24 seconds is the average amount of time between when a
customer queues a newsletter and when AWeber completes delivery.

94% of newsletter broadcasts are finished sending within 5 minutes of
when they are scheduled.

98.4% of newsletter broadcasts are finished sending within 30 minutes
of when they are scheduled.

99.34% of all email was delivered successfully in the last 30 days.

0.66% of all email was undeliverable in the last 30 days. (mailbox
closed, non-existent user, etc.)

Average open rate of HTML and Text/HTML newsletters is 29.7% over the
past 30 days.

Sunday generates the highest average open rate of 41.1%, followed by
Saturday at 36.7% for newsletter sent date.

Average Open Rate by Sent Date: (higher is better)

Sunday 41.1%
Saturday 36.7%
Wednesday 34.0%
Friday 32.8%
Tuesday 29.6%
Thursday 24.6%
Monday 23.2%

Sunday generates the fewest undeliverable bounces at 0.36% for
newsletters sent on that date.

Average Undeliverable Rate by Sent Date: (lower is better)

Sunday 0.36%
Saturday 0.45%
Friday 0.47%
Thursday 0.56%
Wednesday 0.77%
Tuesday 0.83%
Monday 0.88%

Monday is the most popular day of the week for customers to send
their newsletters with 17.1% of newsletters being sent.

Percent of newsletters being sent by customers weekly:

Monday 17.1%
Tuesday 17.0%
Thursday 16.2%
Wednesday 15.8%
Friday 14.5%
Saturday 10.3%
Sunday 9.0%

An 8:00 AM EST send time generates the highest open rate of 50.6%.
Interestingly sending at 9:00 AM EST has a significantly lower open
rate of 33.7% with the worst time to send being 3-4 AM at only 19%
open rate.

Plain text messages are the most popular format of sending newsletters
with 65.9% of all newsletters sent. Mime format Text/HTML messages
follow at 23.8% and a remaining 10.2% of customers still send HTML
only messages even though it is strongly recommended to always include
a plain text version.

Plain text messages generate the fewest undeliverable bounces at
0.46%. Mime format Text/HTML follows at 0.56% and HTML only messages
have a whopping 1.09% undeliverable rate. This is a significant reason
behind our recommendation to always send a plain text alternative with
HTML formatted messages.

Subject line personalization using the date generated an average open
rate of 51.4% compared to personalization using the subscriber's first
name generating 40.9% open rate. Newsletters sent without
personalization of any type in the subject line generated average open
rates of 28.9%.

17% of customer newsletter subject lines sent in the last 30 days
contained date personalization while 19% used the subscriber's first
name. 56.3% of subject lines did not contain any type of
personalization.

Interestingly, using the subscriber's full name or
last name generated lower average open rates at 20%.