Building your list is a very important tool that online businesses should take advantage of. If people don’t purchase anything at that time, then maybe in the future they will. If you get their contact information: name, email address, mailing address (optional), phone number (optional), you can keep them informed on future specials or deals and eventually convert them to be a future buyer of your product or service.
The only thing is getting people motivated enough to sign-up for your newsletter when they visit your website. People are more reluctant to give away their email address now because of so much spam nowadays.
Here are a few tips you can use to promote people to sign up on your website right away.
I hope this helps. Please let me know if there are other ways you promote your sign-up form on your website.