What are one way links and how are they different from reciprocal links?

Any website is said to be linking using a one way link if any other website places its link without asking for a reciprocal link. Often you find many websites useful for your visitors and place their link on your website so that visitors surfing your website may surf those websites and gain advantages from the information on their websites. Some directories offer free one way links while others ask for a reciprocal link or offer sponsored listings for many websites. Article directories too offer one way links to websites that submit articles to these directories. One way links truly increase incoming/outgoing link ratio and add traffic to your website. Reciprocal linking is one of the off-page optimization techniques.