Reciprocating Links

Reciprocation: Repaying an obligation. Humans feel obligated to repay a gift from others.
Reciprocation is a social norm that obligates the recipient to repay a favor in the future.
This ensures continuing relationships which sociologists say is beneficial to society.
On the Web, you can use reciprocity and rewards to increase the likelihood that customers
will provide you with their contact information. You can use free online tools
and multimedia downloads to induce the recipient to give her contact information.
You can also request contact information from your customers before the fact, in
exchange for content. Site owners often trade a free white paper for an email address,
for example. Reciprocation in the form of asking for contact information after the
fact has been shown to be more effective in getting detailed contact information than
reward (asking for contact information before the fact).