Use blog.domain.com or socialbrand.com?

[BenRWoodard]

I've got a little bit of a dilemma.  A company I'm working for has an ecommerce site that is moving to Volusion.  It is impossible to add "domain.com/blog" so I am forced to use a subdomain in order to keep consistency.

We are starting a push in Social media and have secured shorter handles for the brand to use on the different networks.

One of the main goals originally for developing a blog is to build trust but since the domain names are so big (26 characters) and the ecommerce sites already have a good amount of trust building factors in them I am beginning to question my original plan.

My question is this: If I go with a shorter brand recognized domain name to develop the blog on which is different than the ecommerce domain (keyword matched) will I loose too much trust and ranking opportunity because of the difference in domains.

I know there isn't a golden bullet for this question but i would love to get you your take on it.

[EricaMcGillivray]

You'll definitely lose the authority inherited by the current long domain name. Especially if shorter domain is a brand-new domain. That said, these days everything you put through Twitter (why I assume you're looking for the shorter domain) is auto-shortened by their service, which Googlebots read through.