It might be for various reason.
1. Spam (if you create spam post then forum member will report against your post and as a result your post will be deleted by moderator)

2. Off topic (You have t post on on topic. If your post is off topic then it will be deleted. For example if you post your service related topic on altcoin discussion then it will be deleted.

3. If you create multiple post on a single row then all posts will be deleted except 1 post.
There might have many more reason.


I have noticed only 1 topics deleted of you.