A blast furnace is used to create pig iron from iron ore. It is a large vertical chamber lined with refactory (heat resistant) material into which iron ore, lime and charcoal is dropped. The charcoal is burned, with the help of compressed air blowin into the bottom of the chamber via ducts called tuyere's. This generates enough heat for the charcoal to react with the iron ore, effectively stripping out the excess oxygen and leaving the iron behind. After the process has run for some time, the impure pig iron is drained from the bottom of the chamber. The pig iron gets its name from the grid of ducts the iron was drained into, because it resembed piglets suckling alongside the mother.
Your best bet will be to give away something that’s valuable to your target market; for instance, a high-value digital asset on a niche topic. You can give away products (we’ve all seen contests where the prize is a free iPad or gift certificates), however this strategy often leads to entrants who are more interested in the money than in what you have to offer. http://www.mailigen.com/blog/wp-content/uploads/2017/01/guest-blog-feature-1.2.32.png
There are many vendors out there who sell lists or rent them (though renting means that the list seller maintains ownership and control of the email list). These are collections of email addresses that the vendors sell to any business or individual who can pay the fees. Your email list is considered to be a purchased or shared list if it’s provided to you by a third party, like an email list vendor or affiliate. There's a few ways that vendors build these non opt-in email lists.