Does email newsletters adopting a double opt-in procedure (site
visitor inputs email address to sign up to an email newsletter, and
then receives and email to which they must respond in order to really
be signed up) receive less signups than one which is a single opt-in
(site visitor inputs emails address, and then receives an email which
has instructions for leaving the list -- and are kept signed up unless
they choose to unsubscribe)? If so, by what percent less on average?
My company is thinking of changing our single opt-in list to a double
one, and I want to make sure we don't lose too many signups this way.

Ahhh, the age old question of double versus single opt in ezine
subscribers. This is a highly debated subject online and for many very
good reasons. I publish 3 ezines myself with over 12,000 subscribers
and use single opt in only for my subscribers. I do this because from
what I've read people are basically lazy and will not take the extra
step needed to confirm an email subscription. Some will but you'll
lost many subs who never complete the process. It's a fact.

There are some good point to double opt in and if you do some research
you'll find good reasons to use this method.

I searched at Google for "problems with double opt in ezine
subscribers" and came back with many good articles for you to read.

Here's a quote from the ezine experts over at Ezine-Tips the ezine
that caters to ezine publishers.
http://ezine-tips.com/articles/format/20011220.shtml

Benefits of Double Opt-In:

"You reduce the risk that someone will forge addresses, especially to
trivial or offensive newsletters and email-marketing lists."

"You also reduce the risk of being labeled a spammer and losing your
Internet service, because you can show that every recipient asked to
be there."

"Your subscriber base is more valuable to advertisers because they
also know that subscribers are there by choice, not chance."

Moving onto the benefits of single opt in Ezine-Tips had this to say:

"You can build a list much faster if you send a subscriber
confirmation rather than waiting for subscribers to confirm. Some
figures show only 50 percent or fewer subscribers confirm."

"Single opt-in works for newsletters that appeal to a niche or tightly
focused market that pranksters are less likely to frequent."

As you can see double opt-in will cut down on bad email addresses and
spam complaints but it will take longer to build your list based on
the "lazy factor". The quality of a double opt-in list may also have a
higher perceived value by ad buyers since the subscribers had to take
an extra step to actually be subscribed thus may be more committed and
pay more attention to your writings and thus be more responsive.

Ezine-Tips polled some of their readers for their feelings on double
versus single opt-in and you can read their comments here:

http://www.ezine-tips.com/articles/format/20020107.shtml

As far as statistics for how much more slowly a double opt in list
will grow, see what Ken the editor for iMarketing News has to say at:
http://www.rayjutkins.com/ezine/20020219.html

"Double opt in is a perfectly fine way to build a list. We use it for
our e-mail newsletters. But it results in lists that grow 40 percent
to 60 percent more slowly than single opt in, where the list owner
sends a confirmation e-mail, but registrants need respond only if they
don't want to remain on the list."

Some ezine publishers use a combination of single and double opt-in
depending on where they are getting the subscribers from. If you are
buying opt-in subs you should use double opt in methods where as if
they are subscribing at your website single may be fine.

Habeas did a white paper on why confirmed opt-in is better and you can
read their well detailed report here
http://www.habeas.com/about/roi.pdf of course they may have financial
reasons for coming to their conclusions as they sell a special header
to ezine publishers along with a license fee to ensure  that their
ezines are getting through and not deleted as spam. To learn more
about Habeas and what they do see their main website at
http://www.habeas.com/about/overview.htm

A quote from Habeas's white paper

"In a typical case ROI for a confirmed opt in list may vary from 33%
to 102% as compared to only -6% to 58% for an opt in list"

So back to your question, which method is best. As you can see they
both have their advantages and disadvantages. If you're trying to
build your list fast I would suggest you stick with single opt-in of
course with the changes in spam and the laws that law makers are
trying to pass you may want to plan ahead and go with double opt-in so
you always have proof of each and every sub in case they cry "spam".

Good luck to you and I hope this information will help you make a
decision that is just right for you and your list.

Best regards,

Merle-ga

Excellent extremely helpful! Answered my question and included very
relevant related informatio as well. Thanks so much.