I hope this helps
From Wikipedia
Link Bait
"Link bait is any content or feature within a
website that somehow baits viewers to place links to it from other websites.
Matt Cutts defines link bait as anything "interesting enough to catch people's attention."
[3] Link bait can be an extremely powerful form of
marketing as it is
viral in nature."
Link Exchange specifically
Reciprocal Link
"A
reciprocal link is a mutual link between two objects, commonly between two
websites to ensure mutual traffic. Example:
Alice and Bob have websites. If Bob's website links to Alice's website, and Alice's
website links to Bob's website, the websites are reciprocally linked. Website owners often submit their sites to reciprocal
link exchange directories, in order to achieve higher rankings in the
search engines. Reciprocal linking between websites is an important part of the search engine optimization process because Google uses link popularity algorithms (defined as the number of links that led to a particular page and the anchor text of the link) to rank websites for relevancy."