I would love to hear your thoughts on this topic.
I'm basically just "thinking out loud" with the rest of you...

Basically, what I recently did was set up around 20 sub-domain
for my "core keywords".

For example: dog training, dog videos, dog tricks, etc...

Then, I get links into each sub-domain and I post snippets
of articles that go on those pages.

I'll talk more about that part of the strategy in another post.

HOWEVER -- the question is: what is better for rankings?

Creating sub-domains or not?

Here's my thoughts (and I'd love to hear yours).

PLUSES:

- If you look at about.com - that's their formula.
Create sub-domains for each "area". Obviously
works for them.

- Google ALMOST sees this as it's own site.
(which is a negative I'll talk about in a minute).
However, it's positive on the side that you can
possibly get multiple rankings for the same
keyword in the same search engine. (However,
I think that is "old news" see below)

NEGATIVES

What are the drawbacks to using subdomains?

Each subdomain would be looked at by search engines as a new site, which means you will need to do everything you would normally do for a new site.In short, creating back-links, battling the sandbox, and all other problems associated with domain development are still present. If this sounds like too much trouble, you may want to consider creating subfolders within the domain.This would look like www.mydomain.com/folder.
(taken from: http://www.isedb.com/db/articles/1424/0/Subdomains---What-are-the-SEO-benefits/Page0.html)

HOWEVER - THAT IS OLD NEWS.

http://www.seroundtable.com/archives/015621.html
WebmasterWorld administrator tedster has informed us that Google will be treating subdomains like they treat folders on a site. In short, he said, Matt Cutts said Google will roll out in a few weeks a new filter to make sure only two results of a domain (no matter subdomain or folder) will show up for a search. Here is tedster's exact quote from a WebmasterWorld thread:ews flash from Las Vegas PubCon. Matt Cutts informed us that Google will very soon begin treating subdomains and subdirectories the same in this fashion: there will be only 2 total urls from a domain in any set of search results, so no more getting 3, 4 or however many spots via subdomains. We didn't get any more information than just that basic heads-up.

So the conclusion seems to be that it doesn't matter much...

Here's the "final word" from Google's Matt Cutt:

"My personal preference on subdomains vs. subdirectories is that I usually prefer the convenience of subdirectories for most of my content. A subdomain can be useful to separate out content that is completely different. Google uses subdomains for distinct products such news.google.com or maps.google.com, for example. If you’re a newer webmaster or SEO, I’d recommend using subdirectories until you start to feel pretty confident with the architecture of your site. At that point, you’ll be better equipped to make the right decision for your own site."

Enough "thinking out loud"...
Matt

If the rumor is true, and I think it's long over-due, then the only difference between subs and folders is that subs are harder to set up and a lot harder to move.

Again if true and both will be treated the same, it's hard to come up with a reason to use subs, other than for branding.

It will be interesting to see if this will affect link juice coming from subs...

I'll answer this from a technical perspective.

I use both but I do avoid sub-domains at all costs. Why? Number one cause of tech support tickets trying to get things to work.

If you can't build, you can't rank.

I am following up on your master massive site plan Matt and made the decision to build it out with subfolders.

A portal type site for a broad niche that has a subfolder install of the following:

WordPress MU
Article Dashboard
OsCommerce Shopping cart
etc.

Everything works fine out of the box as subfolder installs.

I can't think of any advantage to use subdomains - ranking or technical.

My current "diamond site" has sub-domains but it
will be my last.

Sub-folders here we come!
Matt

Because of these changes the linking "value" will change too.
If subdomains are considered as subdirectories :
1) this means each subdirectory is a considered as a site or NOT ?
1a) if considered as site : not much change for linking value
1b) if considered as part of main domain (so yourdomain.com), this will add a lot more value for the complete domain name

Your thoughts please

Tasari

This should mean that sub.domain.com will be treated as domain.com/sub, which is both are the same domain.

Again, the only reason I can now see for subs is for some cool "word play" for branding.

One example is I have the following sub set up:
news.pheeds.com

This would be good for branding...

So it is considered as 1 site, so then the value of the multiple subdirectories could help your site in general ! So sites with subdirectories / subdomains will be seen as better, right ?

Tasari

I imagine it wouldn't be difficult to convert a subdomain site to a subfolder site, apart from the inbound linking. But if you control all of that .... hmmm

Isobel

Hi Melvin,

I have a feeling that Google will treat high authority sites just a little differently.

But if the new guidelines are strict, what you'll see is just one result from blogspot.com or wordpress.com for any particular keyword search, regardelss of subdomain.

Other subs will still be "indexed" and should still have linking value, but won't show in the SERPs.

It almost seems like a "land rush" and that we should try to get the good subs on the major third-party sites, like blogger, wordpress, hubbpages, squidoo, etc.

Instead of :
=> creating a main domain via WHM, then create subdomains via its cPanel (so Google sees everything as the same)
do :
=> creating a main domain via WHM, creating another domain name via WHM as subdomain, so domain for example name subdomain.domain.com

Does this work ? Would solve the Google problem for those that can do this

Tasari

I don't understand the advantage you're trying to gain. Why not just use the domain as a seperate domain?

So the subdomains would be SEEN differently than the main domain and not like the same... jsut sharing it !

Tasari