22. Advertising (this includes mining pools, gambling services, exchanges, shops, etc.) in others threads' is no longer allowed, including, but not limited to, in altcoin announcement threads. [8]
It is clear from the unofficial rule #22 quoted above. If you advertise your service in threads of other companies or people, it is considered as spam. Honestly, about months ago, in late of 2019, I saw one guy provides such spam advertisement with more than one hundred posts with same contents (that poster only changed name of project for each topic in which he posted).
official thread" on the meta section? IMHO This is a gigantic paradox.