That is only part of the truth. Here
you can find a tutorial to merge blogs into muse sites.
Beware of the issues left undescribed in the Adobe video...
1) If you frame a blog, it is more likely that visitors will discover your blog and not your web site through a search engine. The external blog will rank higher in search results and load without the wrapper of your Muse site.
2) If you use the other option of Business Catalyst, you will need to pay for Business Catalyst hosting. That means a yearly cost between $384-$444! This makes little sense when someone can set up a free customized blog site at places like Wordpress.com or Blogger.com