One Way Linking - Two Way Linking - Three Way Linking

One way linking:
Getting link back to you site from another site is called one way linking, in which you are only putting link in other site, but not receiving that site link on your webpage.

For example:
Your site -- www.abc.com
Other site -- www.xyz.com

In one way linking, abc.com will place its link in xyz.com, and it will give you backlink. www.abc.com --> www.xyz.com

Two way linking:
Two way linking also called reciprocal linking, in which you have to give link back to all those site from which are getting link back.

For example:
Your site – www.abc.com
Other site – www.xyz.com

In two way linking, abc.com place its link in xyz.com and same way xyz.com place its link in abc.com. It like give and take relationship

www.abc.com --> www.xyz.com
www.abc.com <-- www.xyz.com    

Three way linking:
The webmasters who own multiple sites are basically involved in three way linking. They used to get link back through his own websites.

For example: One has 3 websites.
www.site1.com
www.site2.com
www.site3.com

Now site1 place its link on site2, site2 place its link on site3, site3 place its link on site1. This technique is called three way linking.

Why one way linking?
One way linking is most preferable and ethical technique. I strongly recommend going for one way linking program rather than two ways or three way linking.

Advantages of one way linking

1. The most easy to create one way link.
2. Less time consuming.
3. More effective rather than two way or three way linking.
4. Ethical way of link building.

Why not two linking?

1. Two way linking (link exchange) have few disadvantages as listed below.
2. Search engine can easily identify link exchanged links, they give high preference to two way links.
3. Its not sure how long you link will be visible on other website, they can remove it any time without information.
4. You can’t control the placement of your reciprocal link, other site can place your link anywhere in their whole site.
5. Reciprocal link might be coming from the page which itself contains thousand of out going links which reduce the quality of your back link from that site.
6. Links to other website on your website, directs traffic to other sites from your site.

Why not three way linking?
Most people appealing in 3 way linking are doing it with the express goal to control search results. This usually means they are trying to make automated bots think their ideas are better than they are, and are willing to do deceptive things to do it.

There are legitimate reasons to do three way links, but most of the three way link partnerships I have been offered are not worth.

The real problem is that if their two sites are not connected and they are primarily working to benefit the link popularity of their main site then it does not really hurt them if the site linking to you gets banned. If those sites get banned then they parse no link popularity to you.

In doing this webmasters can agressively market their high margin websites while keeping them somewhat shielded from the dangerous effects of their aggressive promotion.

In fact many marketers might set up 20 or 30 or more secondary sites to change links with.