We have a few websites that all deal with the Australian Mining Industry. Here are the sites:
The Mining Jobsite
The Mining Blog
The Mining Showcase
What I am wanting to know is... Is it better to keep the sites as separate domains, or should I just make them subdomains (ie miningjobs.miningreference.com etc), or should I just make them sub-directories under the main domain (ie www.miningreference.com/miningjobs/ etc)?
In particular, I am looking at this from a Search Engine Ranking point of view.