ADDITIONAL INFO (source code) here:
#!/usr/bin/env rubyrequire 'rubygems'require 'blogger'require 'mechanize'require 'set'STDOUT.sync = truegmail_url = 'http://www.gmail.com'gmail_username = 'username'gmail_password = 'password'blogger_blog_id = '12345'blogger_blog_name = 'blog_name'blogger_id = '1234567890'blogger_username = gmail_usernameblogger_password = gmail_password# log in to your gmail accountagent = Mechanize.newpage = agent.get gmail_urlform = page.forms.firstform.Email = gmail_username + '@gmail.com'form.Passwd = gmail_passwordpage = agent.submit form# get the list of ids as per google readerreader_ids = Set.newpage = agent.get("http://www.google.com/reader/atom/feed/" +"http://#{blogger_blog_name}.blogspot.com/feeds/posts/default?r=n&n=100")page.body.scan(/https\:\/\/blogger.googleusercontent.com\/tracker\/\d*\-(\d*)\?/).each do |id|reader_ids << id.to_send# get the list of ids as per bloggeraccount = Blogger::Account.new(blogger_id, blogger_username, blogger_password)if account.authenticated?blog = account.blog_for_id(blogger_blog_id)blog.posts.each do |post|reader_ids.delete(post.id)endend# the following posts have been deletedreader_ids.each do |id|puts idend