Steempeak.com you can post whatever you want on your blog.
Each of these new communities has a rule set (or maybe they dont have rules)
But there is a community called steempeak community. That communities rules are on the community page. That particular community has stated its purpose in the rules that its content is about steempeak.

Steempeak.com is gonna make a change to help users see the rules of a community prior to posting so they dont have to go into the community each time to read them. Maybe steemit.com will also make that improvement for users.