Ensuring requested opt-in email is delivered to subscriber inboxes is an increasingly difficult battle in the age of spam filtering. Open and click thru response rates can be dramatically affected by as much as 20-30% due to incorrect spam filter classification.
Confirming that the people who ask for your information have actually requested to be on your list is the number one step in the battle for deliverability. You should be using a process called confirmed opt-in or verified opt-in to send a unique link to the attempted subscriber when they request information. Before adding the person to your list they must click that unique link verifying that they are indeed the same person that owns the email address and requested to subscribe.
When requesting website visitors to opt-in ask for their “real” or “primary” email address instead of a free email address like Yahoo or Hotmail. Free emails tend to be throw away accounts and typically have a shorter lifetime than a primary ISP address.
Your web business probably gets product inquiries from potential customers around the globe. Inquiries come via e-mail and your web site, and you try to send information to each hot prospect as quickly as you can. You know that you can drastically increase the likelihood of making a sale by satisfying each person's need for information quickly!
But, after you've delivered that first bit of information to your prospect, do you send him any further information?
If you are like most Internet marketers, you don't.