How can a positive post be considered as spam?
If it were not spam then your posts is probably "off topic" I've just translated the thread where you posted and I seem to agree that your post (containing content from the OP) is off topic.
The thread is self-moderated. Is this the reason for which thread creator can do whatever they want?
Actually yes the creator of the thread can do whatever they want like to delete post etc. but of course as long as it is inappropriate to the thread
The thread going to be a total trash because thread creator is deleting good post instead keeping them alive and deleting the spam.
No rule for this?
How can you assure that the one who deleted your post is the OP of that thread?
1. The thread is for discussion about cryptocurrency in Bengali. Paidexbd offers BTC to BDT. Since, there's no seperate board for Bengali language, this thread is the place for discussion on cryptocurrency and all related to cryptocurrency. I don't get how you find my post off-topic but my post isn't off-topic by any how.
2. If the thread creator has the power of manipulation, why this thread has been sticky? Either there should a local section or that thread should be out of manipulation.
3. I can assure because thread creator said couple of times in that thread that he had deleted the spam.
So it means moderator found it off topic or it is breaking some rule.
So, someone reported my post. I don't know how it works. There's no moderator who understand the Bengali language. Did moderator delete the post because someone reported? No further looking before deletion?