I recently updated an eBook which I wrote which covers a lot of tips and information related to internet marketing. To coincide with this update, I decided to change up the avenue through which I release it, as well.
While in the past I was offering it as an incentive to encourage people to sign up for my email list, I've now decided to give it away in a different way.
Now while I'm still giving away the updated eBook at no charge, the difference now is that you need to "Like" and "Tweet" my site and about the offer, respectively, in exchange for the download link which I think is fair given the breadth and depth of content contained in the eBook.
What are the advantages of requiring social proof / interaction?
First, you want to require people to do this because it strengthens their loyalty to you. Secondly, it makes for free advertising for your site and brand. This is because any one of that person's friends or contacts on that social network could notice that they are tweeting about or liking your page or brand, thus increasing the odds that someone else will check out your site, especially depending upon how you brand your site to begin with.
Additionally, social proof is playing an ever greater role in social search. In other words, social proof accounts for one of Google's ranking factors and will help your site rank better. This is because Google sees this as someone's virtual thumbs up or vouching for your website; the thought process is your content must be good, hence the social proof, so let's rank it more highly.
You can't just expect someone to "like" your site and click on these social interaction proof buttons without giving them something in return which is worth liking, so you can use an incentive as an obvious way to do just that.
I use a free plugin called WPLike2Get which will hide content on your page or downloads until someone gives you the desired social proof you want. You can choose to make someone "Like", "Tweet", give you a Google +1, or some combination of all three before they can access the desired content, making it a very effective way to require someone to give you this advertising and proof before they can see or download whatever content it is they want that you have.
The "Like" and "Google+" are pretty straightforward but the Twitter setting is especially nice because you can get people to Tweet what you want them to as it will prepopulate the field for them.