Recently I did setup a blog site for corporate client. This blog is only for company employees, its dealers/retailers business partners and other people related to core business. This blog is immediately pickup by both Google and Yahoo search engines.
They send me new request to remove blog from Google and Yahoo!. LOL, which is beyond my control. Anyway, I found a Google webpage that remove indexed data.
Next, I put entire blog in password-protected directory and I am working on wordpress plugin that will allow only authenticated user to see blog entries.
To be frank, blogs are available on the Internet exactly like other webpages. The only way to keep any blog (including wordpress, blogger.com and other all blog software) hosted on your own server is to put in password protected directory from both Search engine and guest users.