As I mentioned above, this post was written in the community using steempeak (case 1). It appears as follows:

• in the community hive-119826 (https://steempeak.com/c/hive-119826/created)
• on ctptalk.com (https://www.ctptalk.com/@achim03.ctp)
  It doesn't appear however in my blog (https://steempeak.com/@achim03.ctp)

My conclusion is this (case 1):
If we post in the community using no tags it will show only there. But then our post will not be elegible for CTP tokens.
If we add the ctp tag, it will be visible in the community and on ctptalk. It will be elegible for CTP tokens.
To be visible on our feed the post needs to be resteemed.