The following is a description of links for Search Engine Optimization and what they can do for your site.
One Way Links … The Natural Ones: When search engines are ranking a site, they look for sites with authority. Having links from multiple related sites is one such method of gaining authority. The best type of links for doing this are one way links in which a site links to your site, but you are not required to link back to their heads. These links are based on how good your content is and the resources you offer. Ways of getting one way links include submitting your website to directories and asking webmasters of related sites to include a link on their page.
Catch Links with Link Bait: This creates creating images, videos, content, or anything else of high interest that will cause people to want to link to you. Some examples include mortgage calculators, website grading software, funny videos, etc. This is a very successful way of gaining links and is very budget friendly. Use this in combination with social bookmarks and you can generate tons of traffic.
Paying for Your Links: Looking for websites in your chosen niche and negotiating a price for a link back to your page, is another way of gaining links. However, Google seems to penal websites that do a large amount of link buying and these sites tend to lose their rankings in the search engines if too many paid links are discovered. For newer sites, this can be a major problem so this form of gaining links is only recommended for older, more established websites.