Dealing with domain name change that initially was aliased

Do I stay with an alias or change to a redirect?

[zorvek]

I have a website that I am working on where the company changed its name and domain. When they did this they used an alias for the old domain. Does anyone have any experience working with aliases and search engine spiders?

A few observations thus far:

- On Google both the aliased name and the current domain appear to be treated as if they were one and the same for many searches. In some cases the Google listing will list the new URL and link to a page that displays the old URL and vice versa.

- The PR for the new URL is 6 and the PR for the old URL is 5.

My questions:

- Is this likely to be causing any problems for the rankings? Is it possible it will hurt more in the future? Less? I have seen some postings stating that aliases are treated intelligently by Google but not so for some of the other search engines.

- In the past I have heard that search engines prefer redirects over aliases and, in some cases, even may consider aliases to be spamming. What can you tell me about this?

- There are many current SE links to the old URL that go to interior pages. What is the best way to deal with these? We do not want to lose the links.

[ciml]

Welcome to WebmasterWorld, zorvek.

As far as I'm aware, having identical content at the URLs should be fine. If Googlebot finds no differences, then they should be merged in the index and the backlinks and PageRank should be combined. If the content varies slightly between the two URLs, or if it changes slightly between the times that Googlebot visits them; then you could have both URLs listed for the same searches. If taken to extremes this can annoy people, and of course splitting the backlinks gives you less chance of a high position.

With enough PageRank, a link to a URL with HTTP 301 redirection should pass PageRank to the destination URL. There have been reports [webmasterworld.com] of odd behaviour recently but in the situation you describe I'd still probably opt for this approach.