Subdomain VS Subdirectory in SEO

Can you help me with this guys?


What are most often good in SEO and ranking?


A subdomain? blog.domain.com
or
a subdirectory ? domain.com/blog


Anyone can share your experience and ideas?


In terms of blogging, and landing page.
Thanks a lot guys.

I agree with Ryan - the rule is that subdomains are treated as separate sites by the SEs or at least that used to be case (not sure if still valid after the most recent changes). I would go with a subdirectory if I were you

Subdomains are considered entirely different. So if you had http://dogs.animals.com and http://cats.animals.com you may as well have http://www.dogs.com and http://www.cats.com
Subdirectories are merely for organizational purposes and is considered the same site.

Generally, Sub-directories are better. Though I use subdomains all the time (ie: wiki.site.com, forum.site.com), more for practicality reasons or very specific circumstances (ie: custom rendering of site in a sub-domain that replaces the logo etc).

That said, different site structures may require different architectures so you might want to do different types of backlinking if the structure or logic is different. That way subdomains would be preferable however you might as well get a new domain for that like Zapdos suggests (unless costs are a factor, ie: 1000s of subdomains).

To be honest, this would solely depend on the situation and purpose to purpose. I would with what Ryan have mentioned but make sure you work on things based on your requirements and not exactly what everyone says.