Some ad platforms will ask more of your landing pages than others, when running ads. For example, AdWords is much stricter, when compared to Facebook. AdWords typically requires that you do not have a ‘thin,’ site that is designed solely to collect leads. Because of this it might be a good idea to focus on using Facebook or Twitter, to begin with.
It’s a best practice to ask the referrer not only for a friend’s email address, but also for a full name so that the message is personalized. Most important, remember to add the referee’s full name to the email as well. By referencing whom the email content was recommended by, you gain instant credibility and will attain much higher conversion rates.