Content Locking is one of a type of incentivized CPA (Cost Per Action).
Basically, through content locking CPA network, you can upload mainly anything you want (no porn, no child abuse or wifi hack) and then you promote your content or resource online.
Your locked content can be in the form of software, ebook, mp3, video, etc. and even your web content or links.
The goal is that the visitor that want to view or download your resource, will have to complete an offer or a small survey or to download and install free trial software, in order to get access to it.
Depending on the setting or the lockers from each different networks, the content will be unblocked immediately and will be blocked again after few minutes or few days. The IP address of the user is used to determine the number of time he has accessed to the resource and such the permission for him to gain access them.
The amount you get per offer completed differs from the type of offer and his location and it is between $0.10 to $30 or more.
Here is an example of content locking :