The big difference is that people will be giving you their contact information voluntarily. Also, you know these people value what you offer—especially if you pick a prize that is particularly desirable to your buyer persona. For example, if you own an HVAC installation business, give away a prize related to home improvement that will attract homeowners.
I am a scientist. My e-mail has been drawn from publicly-available sites related to science. My name and e-mail is being sold as part of a 7 Million+ e-mail list to biomedical companies and anyone who wants to buy targeted lists. I NEVER gave permission to use my name and e-mail and in fact requested that my name be removed. The company continues to make profits by selling my name + 6.999 million others. I don’t care what country you are from, this is UNETHICAL and ILLEGAL (in my eyes). Of course, who as the money to try and persecute such crooks? Worse yet, if I live in South Africa and the company is selling from India, how can US laws affect or cover me? These guys work across transnational borders because they know that they can operate across international borders online, without any regulation (unless they operate from the US, perhaps). So no fear, no penalties, no recrimination, no fines, just sickening profits from unjust and unfair and illegal marketing methods. Because frauds all abuse innocents.
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.