If someone didn't ask to hear from you yet, it doesn't mean they won't want to hear from you later. It's your job to prove to them -- through helpful content and valuable offers -- that they should stay up to date with your company via email. If you force your email content on anyone too early, even if you know in your bones they're a great fit for your products or services, you risk preemptively losing their trust and their future business.
A common example of permission marketing is a newsletter sent to an advertising firm's customers. Such newsletters inform customers of upcoming events or promotions, or new products. In this type of advertising, a company that wants to send a newsletter to their customers may ask them at the point of purchase if they would like to receive the newsletter.
InfusionSoft is a fully functional CRM and marketing solution created for small and medium size businesses. Comparing it to MailChimp or AWeber is like comparing a Lamborghini to a VW Golf. It provides highly advanced features for list segmentation, lead scoring and marketing automation. On top of all that, you can integrate all of these features with your optin form using Infusionsoft Tags + OptinMonster.