FOR EXPERTS:301-Redirect of thousand of subdomains...

Hi,
my SEO team has been given the management of a portal dedicated to pubs.
The portal structure is quite strange.
Any single pub does not have a dedicated page like www.domain.com/pubname.htm, but an entire subdomain like http://pubname.domain.com
So the site is actually composed by thousands of subdomains, redirecting to a corresponding subfolder (it's not a meta or javascript redirect, it's a server-side redirect)... don't ask me why the previous webmaster projected this insanity, nobody has been able to give us a sensible explanation up to now (would you? ). Whenever there was a new pub to add, he added a subdomain with redirect (they didn't have any CMS or similar..)

When I check the site on Google (SITE: command), Google displays only the subfolders URLs like www.domain.com/pubname.htm, BUT I know that all the subdomain URLs are indexed too: when the site ranks for a keyword, it's always the subdomain URL (http://pubname.domain.com) showing up in the SERP.
Checking on link popularity, I found out that the subdomains don't get outbound links (from other sites), but only inbound links.

Now, the client asked for a site restyling and a new site backend; they naturally don't want to lose traffic from search engines (90% of traffic comes from search engines).
What we are going to do now is eliminating the foolish subdomain site structure and leaving only the more reasonable and natural subfolder structure.
We are going to 301-redirect all the subdomains to the corrisponding subfolder, in order to leave only the subfolder URLs in Google's index (which Google had already completely indexed and ranked). Of course, we expect a fluctuation of our best rankings, but on the long distance, we think we'll keep more or less the same rankings through the subfolder URLs. The site has PR 4, the subfolders show PR 3.

What do you think? Has anyone had a similar experience? Not with thousands of subdomains, maybe hundreds...

thanks

 

The site will see fluctuation if you plan on doing 301 redirects, which in my mind is useless and is more work than it's worth. The setup the site this way to get the subdomain URL version to show in search results, I'm assuming they are using 301 server-side redirects already.

 

as far as I know, a 301 redirect removes the URL permanently from Google's index, but the subdomains URLs are still present in Google's index. It's like Google has stored in its index both URLs (subdomain and subfolder), but decides to show up the subdomain in the SERP. My question is: If I remove the subdomain type URLs, will the subfolders URLs rank at their place? If not immediately, after a short time?
Thanks again to all

 

Correction, I ment they are probably 302 redirects, this is how you achieve what they are doing. If you want to keep all the backlinks you must keep the 301 redirects in place, since they are sub-domains you must keep the physical setup for the sub-domains.

 

I've seen a couple dating sites use this technique to target numerous long-tail niches. I'll see belgium.dating.com southerncalifornia.dating.com. I suppose it's suppose to carry more weight SEO-wise than a subfolder with the same keyword. e.g. dating.com/belgium dating.com/southerncalifornia Can someone confirm this? Or better yet, registering a separate domain for each long-tail keyword and linking to an original site.

 

subdomains are indeed more effective then subfolders fr long tail targeting and local search