Using contextual link building for a higher ranking with the search engines is by far one of the best search engine optimization strategies. When the context of the web pages you have are a close match to the context on other web pages linking the two together can make the search engines give you extra ranking points for being popular and having a common bond with another page.
If you just randomly try to insert links to your pages rather than doing contextual link building for a higher ranking with the search engines you could do more damage to your ranking than you do good. The content of two web sites that are linked together must have relevance to each other. If the content does not have a relationship to the content from the previous page then the search engines will not see the link as favorable. You have to be careful with your search engine optimization techniques to make certain that you do not disregard any of the regulations that have been established to make the systems work well together and be fair to all web sites.
With Contextual Link such as guest posting service you not only get the opportunity to increase the ranking you have with Google, Bing, Yahoo, and the other search engines, you have the chance to send people who are already interested in the context of your pages to them. With these links the person is viewing a page or a web site that has some of the same general information that you have so they are interested in this information. They see the link to your web site where they are supposed to be able to either get more information on the subject or where they are supposed to be able to make a purchase of something they have been researching. That is a winning combination because all you need is relevant material, the person browsing is already hooked.