I could be wrong, but I believe one of the blogging platforms where you can only read the person's posts if they approve you is
http://www.travelpod.com/, I also believe the one that Good Sam has requires you to allow the person to see your blog. Most ... like wordpress, blogger, etc are open for all on the internet to see.
OK, just checked travelpod - and their premium one can be private: "
Private blogs
With an Enhanced Membership you can make your blogs private, so only friends with the password can read it."
One of my friends uses that.
Beth
“Dare to live the life you have dreamed for yourself. Go forward and make your dreams come true.” ~ Ralph Waldo Emerson ~
"He who treasures the small things in life has found the path to true happiness"