because advertisements will be added to all your outgoing emails. You
will have no control over which ads are shown and this will distract
your subscribers and dramatically reduce the response rates to your
You can either pay a monthly fee and use a third party hosted auto
responder service like Aweber or Get Response, or you can pay a one
time fee and install an auto responder script like Auto Response Plus
on your domain.
The problem with auto responder scripts is that
the number of subscribers you can store will be limited depending on
how much disk space you have with your hosting plan, and you will also
need to backup your list on a regular basis in case a problem occurs
and all of the information is lost.
Its much easier and safer to
use a third party hosted auto responder service because you will not
have to worry about installing a script and your subscribers will be
stored securely on a dedicated server with no limits.
...Double opt in lists are becoming more popular because they provide
extra security as subscribers must confirm their email address, but
many people will forget to complete this confirmation which results in
fewer active subscribers so you may prefer to use the single opt in