Somewhere I remember reading that its bad for SEO for your blog url to be blog.mycompanyurl.com. I can't remember where or why. My host only allows above option. Do you think its a big deal?
Not true at all. SEO business, if you haven't figured out that so far, is chock-full of half truths and nonsense. SEO "experts" don't understand the correlation at all and imply causation on pretty much everything they come across. Most of your PR comes from backlinks so whether you use a CNAME or a directory is quite simply irrelevant.
To my knowledge, what matters Google pagerank-wise is a page, not a web site.
However, if you are going to provide individual homepages for the users of your web site and you want their URLs be mycompanyurl.com/username, like with del.icio.us, then maybe the domain option would be a better choice, and probably not only for your blog but for the rest of your corporate info as well.
They have a one click installer that blows up if the url is not in the format: blog.myurl.com. I put in a support request and told them that I want myurl.com/blog and they said its not supported (by the one click installer I guess)
