Is it bad to no follow all External LInks at the same time?

[Personnel_Concept]

I am working on more than 40 EMDs. They are good quality brand sites but they all are interlinked to each other through footer links, side bar links. (and they dont have much of linking root domains)

Now Some of those sites have been renovated with new templates and these new sites has very few external links (links going out to our own sites) but some of these old sites has 100s of external links (all these external links of course link to our own sites).

But anyways, we are planning to no follow all those external links (links that are linking to our own sites) slowly to avoid penalty?

question is, can it be bad to implement no follow to all those links on those sites at the same time?Will Google see it as something fishy? (I don't think so)

Also, Is it good strategy to no follow all of them? (I think it is)

What you guys think ?

[Personnel_Concept]

Thanks Simon. Yeah I saw that blog.

[Personnel_Concept]

Thanks Marcus. And No they are not doorway pages and they are all proper genuine brand sites. That's why they are not affected by recent EMD update.

[SimonCullum]

That's a great answer from Marcus.

A blog post here on SEOmoz from last week entitled  "The Exact Match Domain Playbook: A Guide and Best Practices for EMDs"  is well worth a read too, check out the section towards the end, "A few things to consider for solving problems with EMD sites".

Regards

Simon

[Marcus_Miller]

Hmm, sounds like you have your own little network of sites so any interlinking of them purely for SEO purposes is going to be problematic. The guidelines page on link schemes has recently been updated and makes for a good read and specially, this point seems relevant:

From - Link Schemes: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=66356

"The following are examples of link schemes which can negatively impact a site's ranking in search results:

• Buying or selling links that pass PageRank. This includes exchanging money for links, or posts that contain links; exchanging goods or services for links; or sending someone a “free” product in exchange for them writing about it and including a link
• Excessive link exchanging ("Link to me and I'll link to you")
• Linking to web spammers or unrelated sites with the intent to manipulate PageRank
• Building partner pages exclusively for the sake of cross-linking
• Using automated programs or services to create links to your site"

It is hard to comment with certainty without seeing the sites but seeing as these are all EMD's there is always the possibility that these are essentially doorway pages that exist purely to capture search traffic and direct them to another site. Again, this is not advisable and to again quote the specific Google guidelines:

From - Doorway Pages: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=2721311

"Doorway pages are typically large sets of poor-quality pages where each page is optimized for a specific keyword or phrase. In many cases, doorway pages are written to rank for a particular phrase and then funnel users to a single destination. Whether deployed across many domains or established within one domain, doorway pages tend to frustrate users."

"Having multiple domain names targeted at specific regions or cities that funnel users to one page"

The bolding in all cases is mine and I have not seen your sites but it's time to be honest and ask yourself if these sites exist purely for these reasons and then further debate the value of them going forward as a potential negative equity.

To go back to your original point, if you are looking to nofollow the links then I would not worry about any slow or steady approach, just make the changes to be within the guidelines as quickly and painlessly as possible.

As ever, without examples, only general guidelines can be given but all too often these kind of EMD sites exist to rank for a specific term and if you are linking back to other sites then they likely are problematic in a variety of ways.

Hope that helps.

Marcus