Backlinks are incoming links to a website or web page. Inbound links were originally important (prior to the emergence of search engines) as a primary means of web navigation; today their significance lies in search engine optimization (SEO). The number of backlinks is one indication of the popularity or importance of that website or page (for example, this is used by Google to determine the PageRank of a webpage). Outside of SEO, the backlinks of a webpage may be of significant personal, cultural or semantic interest: they indicate who is paying attention to that page.
I have been using this method to help with people comming to my GDI site, it is a FREE way to get traffic to my site. I may go to a blog and post a relivate committe on an issue and leave my wesite. This is a backlink and if used currently it will generate free traffic.
Sometimes called inbound links, backlinks are the lifeblood of Search Engine Positioning. In order for a website to be on the top of search engines like Google without the webmaster having to pay big money for advertising, the website has to have a large number of backlinks. Backlinks are links on one website that lead back to another website. The more established, high quality, and high Page Rank the website that contains the link has, the more power it has to help the linked website with its search engine position. If the website that is getting backlinks gets many High Quality and High Page Rank backlinks, the better the chance it has of being in a high position on the Search Engines.
How does a webmaster go about getting high quality backlinks to his or her website? There are many ways this can be done. Some people advocate writing and submitting articles, posting on forums, making comments on blogs. Others talk about submitting their website to various Internet directories. One directory that has an excellent reputation is called DMOZ, or the "Open Directory". This directory is probably the most respected directory online today. The websites it contains have all been placed there by human editors; there is no "automation" to this directory. The only drawback that's been discussed about this directory is that it takes so long to have a website included.
Another way that many people build backlinks for their website is to use Social Bookmarking websites. A "Social Bookmark" is a website that usually has a very popular 'community' aspect to it. Users sign up and create profiles on the sites that contain photos and information about themselves. They then can save "bookmarks" of favorite websites which can be itemized by 'tags', which are one or two word descriptions of what the sites contain, and these bookmarks can be saved to a list that's private or can be listed publicly, so that everybody can see it.