Sub domain vs. sub folder

[s-s]

I know this has probably been asked many times and answered too, but things change a lot, so I would like to know with current search engine algos and co.

The scenario is as follows:

Building an ecommerce site and also want to incorporate a Q&A section, for support and FAQ's and such.

should we go ahead and sub domain this like: community.test.com or rater go with test.com/community.

I would really like to know why, why not and maybe some real life examples.

Thank you all

[Linda-Vassily]

You are correct, this has been discussed quite a bit—the answer is subfolder.

Here is an excellent, recent, thread on the subject: http://moz.com/community/q/i-have-a-blog-on-a-sub-domain-would-you-move-it-to-the-rood-domain-in-a-directory

Here is what Rand Fishkin has to say, with an example from moz.com: http://moz.com/community/q/moz-s-official-stance-on-subdomain-vs-subfolder-does-it-need-updating 

An excerpt from his response: "We recently were able to test this using a subdomain on Moz itself (when moving our beginner's guide to SEO from guides.moz.com to the current URL http://moz.com/beginners-guide-to-seo). The results were astounding - rankings rose dramatically across the board for every keyword we tracked to the pages."