Note: There is an important comment from someone at Worpress that explains the situation, so please read the comment from Tellyworth. Essentially, I'm able to read the blog's archives, but won't be able to read anything which is posted after the blog was made private.
If you use Google Reader, you may be familiar with the "recommendations" function. The software looks at your subscriptions and asks you if you'd like to subscribe to various other blogs or sites based on the interests your current RSS feeds indicate you have.
This is a pretty handy function and I've found some good content that way, though there are often far too many recommendations which are essentially "more of the same." Besides opening up the potential for finding interesting sites, the recommendations feature also shows you just how much cannibalism is going on out there. Many niche blogs are all essentially echo chambers and very few have truly unique content. It'd be shocking how many people create sites by just searching and compiling various other types of content if there weren't money in the equation. If there's profit to be had and someone had too little experience or imagination to create, they just assemble.
When I clicked on this blog to access the original site, I got the message above. The site is password protected to keep the masses out, but Google Reader invites them right in. I don't use a WordPress blog, but I'm guessing you can choose to have your blog listed for RSS feeds or Google searches or not and this person made a mistake. If I could, I'd contact this person and let them know that their private thoughts are out there for others to see via an RSS feed and advise her to check her settings. However, I can't contact her because I can't get into the blog to leave a comment.
The object lesson here is to keep in mind that even when we think we're undercover when we're on-line and even if we take reasonable precautions to keep our personal thoughts hidden, we can be unintentionally exposed. If it is something that you think should not be read by the masses, it might be better not to put it on-line at all.
Update: I wonder if the blog I accessed is only protected in a weak way. That is, perhaps people with Wordpress accounts can get in without any special password if they just log in with their user accounts? Since I don't have Wordpress, I don't know if it carries such limited (and pointless) protection just to keep out random anonymous commenters. Does anyone on Wordpress know if that is possible?