A backlink is a one way link from another website with a pagerank higher or equal to the page on your site it links. These types of links are very difficult to scam hence they are very important in determining the rank of a website in the search engines results.
There is a great tool for seeing your site’s actual backlinks. It is found at http://backlinkwatch.com. The added benefit of this tool is that it shows you sites that are scraping your content which causes duplicate content penalties. Duplicate content penalties force a site into the 1000 plus search results, basically making a site invisible to the searchers. A great tool to see who is scraping your content is found at www.copyscape.com. A site with duplicate content will also lose its pagerank and strength in the search results.
What do you do if you find a site scraping your content?
The easiest is to block the site from accessing your site via a robots.txt file in the root directory of your hosted files as found in the following example:
# blocking people search engines
Note: xyzpeople is for any domain name that starts with the later term. (I.E. xyzpeople.com)
Another way is to block the ip address by editing the .htaccess file root directory of your hosted files (You might have to create the file if not found) as found in the following example:
Deny from 44.444.44.*
Deny from 77.777.777.77
allow from all
Note: 44.444.44.* is for any ip address that starts with 444.444.44 and 77.777.777.77 is for an exact ip address.
You can find out a site’s ip address via http://www.networksolutions.com/whois/index.jsp
So, how does one obtain quality backlinks?
I have found that responding to articles on another site while making sure I have a link back to my site in the signature works well. Also, online press releases done in the later manner works well too. And as always, writing quality blog post on my own site ends up with others linking to them.