[Travis]

Are you sure your motivation is correct, WRT pagerank?

I'd always thought that PR applies to your PAGES only. not domains. So, in your example, it's not that blog.twilio.com has a higher PR than www.twilio.com, it's that the blog.twilio.com INDEX page has a higher PR than the www INDEX page.

Thus, your PR isn't really affected by being on a subdomain, as the juice that flows through the system doesn't care about the sub/domain, only about the page and what points to it.

Please correct me as needed.