I used the Whois tool, but, in blogs cases, it only displays the e-mail address of the blog service (i.e. Blogger, Thumblogger, etc.). Thank you for your answers.
no you can't find out who owns a blog. Untill unless if the blog owner gaves real info then also 10% chances are their to find the owner.
By default, the blogging sites will not show any information personal about the account, that's jump to the privacy. It's up to the blogger to show some of his/her details.
you can see if it owns a full domain by domain whois, rest is on the behalf of owner if owner wish to show its information.
Unlike domain, you can't actually determine who is the owner of a blog unless the owners decides to disclose accurate information and let you know about it.