Read Chris Richardson's article in WebProNews, called "Multiple Domains And 301 Redirects".

This article deals with sites having multiple domain names and problems with redirections. What you must do is choosing one main domain name as the official site and redirecting all the others to this one with 301 redirects. If you want know what kind of redirect you're using, copy and paste the URL in this Server Header Checker tool.

A common area of misunderstanding and confusion within search optimization has to do with how and when one should use a redirection document. If you've moved a site to a new domain and you want your normal traffic to follow, a 301 permanent redirect needs to be employed. However, there are other occasions, also involving domain-based issues, when 301's should be utilized.

Read more.

1) Syntax: link:www.your-domain.com or link:http://www.your-domain.com
DO NOT use space after link:
will show the backlinks of that page which Google knows and decides to show with that command
will show results that contain the text "link" and the text "www.cnn.com"

2) Google doesn't return all backlinks in response to link: command.

3) Google link: command is not updated in "real time" but it is updated approximately once per month

4) Since June 2004 Google returns backlinks which have any PageRank value (and not only backlinks which have a pagerank of 3 or 4 or more as Google used to do)

5) To get more accurate and up-to-date Google backlinks you may use the following command
:www.cnn.com Remark: not all results return by this command are links to www.cnn.com page, it can be just a plain text URL (www.cnn.com) without links mentioned on the page somewhere
:www.cnn.com -site:www.cnn.com This command will show you all the pages linking to cnn.com, minus the pages from cnn.com site.

6) Related Google links tools
Google backlinks and anchor text analyzer
Google ranking software (based on Google API)

7) Articles related to Google link: command

Google backlink strategies

Hope this may help you!

Jon Payne writes about the need for directories subscription in Search Engine Optimization process. He claims that one should submit its website only to the main directories, and more specifically to theme-based directories.

"Anyhow, theme-based directories offer the ability to really provide more detailed, industry-specific information. They also seem to lend themselves moreso to actual human editing, which generally results in higher-quality results and thus a more useful directory." says Jon Payne.