A "one-way text link" means that a Web site links to your Web site but you don’t link back to that Web site. One-way links, also known as non-reciprocal links, are much more difficult to obtain than traditional reciprocal links. In the eyes of search engines, one-way text links have a more natural flow and appear less self-serving. As a result, they are very valuable to your business because the more one-way links you have, the better your chances of an improved search engine ranking, page rank and link popularity.
Example of a One-Way Link
Example of a Reciprical Link
Site A and B both get a very small boost.
Example of a Three-Way Link
These are non-reciprocal links! Site A, B, and C all get a strong boost.