Is sub-domain better or sub-folder? - seo

Question

I have a classifieds site and I want to know whether creating subdomains or sub-folders is better, as I am in state of confusion.
If we need to take sub-domains then what are the benefits which we can get from sub-domains?
If we need to take sub-folders then what are the benefits we can get from them?
If we create sub-domains then Google considers sub-domains as individual domains and would show only 2 results per page.
So please clear my doubts and let me know which one is better.

Answer 1

Search engines will treat subdomains more like separate domains, so it many cases using sub-folders is the way to go, so that you are not spreading yourself to thin.
using both is a bad idea, as search engines will try to index both, and one will get flagged as duplicate content.
Here's an article from SEOMoz explaining it in more detail:
http://www.seomoz.org/blog/understanding-root-domains-subdomains-vs-subfolders-microsites

Answer 2

Personally, I go off the logic that a subdomain is a different application / site owned by the same company. A subfolder is part of the same application / site.
It is probably better for your PageRank / search engine listings if you have 'one-big-site', rather than lots of different loosely coupled domains. If the content of the sites is distinctly different, e.g. a personal site might have a gallery or blog subdomain which keeps the content distinctly seperate from the main site - then it probably makes sense for a subdomain, otherwise, I'd stick with folders.
p.s. Side note, dunno if this is important, but web-browsers only open two connections at once to a website when downloading the different files that constitute a page. So there is a reason for a subdomain in this instance where it actively speeds up (though, on a fast site, minimally) the page load time.

Answer 3

It depends on what content you want to create subfolder/-domains for.
Is it related to your original site? Then you should definitely use sub-folder as this belongs to the same domain. It's much better for the link juice to spread if you use sub folders.
As for the PageRank, it's better to use subfolders.
Subdomains is considered as a new site. Subfolders is not, and will get better rankings if your original site is powerful.
You can use both subdomains and subfolders if you like, but don't forget to use the canonical-tag to avoid duplicate content.
Two relevant links that explains this further:
http://www.searchmarketingstandard.com/when-to-use-subdomains-vs-subfolders
http://www.searchenginejournal.com/subdomains-or-subfolders-which-are-better-for-seo/6849/

Answer 4

Why not both? Have demandb.com/foo and foo.demandb.com go to the same place.

Answer 5

Technically, a subdomain is a different server. The company I work for has a domain with several subdomains where every subdomain is located on a different (virtual or real) computer/server. That way, if one of them crashes, the rest just keeps running.
From a developer's perspective, a subdomain would force everything within the subdomain to be a different application while in a subfolder, the subfolder and subsubfolders could be part of the application in the root folder. When I create web applications, those web applications are often tested first on a test server in a subfolder. Once they make it through the tests, they are moved to the root of their own subdomain.
When two subfolders are related to one another, they're often part of the same application, thus it would be better to keep them in their own subfolder so they can share cookies and sessions more easily.

Answer 6

2 comments:
Use sub folders if you need SSL- then you only need 1 basic certificate for the root
If you use both, make sure you redirect 301 one to the other. That will avoid the search engine duplication issue, but would still be problematic for SSL in certain situations.

Answer 7

If your site can be easily partitioned by the subdomains and each subdomain can operate independently then do it! You can then easily scale out your application by deploying different servers(or clusters) for each subdomain.
Examples:
Craigslist: by region(seattle.craigslist.org, sfbay.craigslist.org, etc)
Livejournal: by community/user
Technically, you can do this with folders, but it requires a web proxy farm, whereas subdomains can be done with simple DNS entries.

Answer 8

its also depends on your needs whether u want separate login system for sub domains, because it wont be possible is you are using sub-folder. Sub-folder share same session.
For sub domains you have to set shared cookie for all domains.