There is no clear answer here. Back in '07, Matt Cutts said that Google does not penalize subdomains or treat them as different sites: http://www.mattcutts.com/blog/subdomains-and-subdirectories/
If your pages are of high value, they will rank for that, but I don't think it does much bad or good for your root site. Just focus on creating great pages and the rest will follow 🙂