Yesterday I created a post about a service to forward bitcoin from exposed keys (called bitdrain).

Today I see my post is completely gone, but I also did not receive any kind of message. Was this post removed by the mods?

-> Why? It does not seem to be breaking any forum rule. One could argue about the potential to be abused but the same goes for any brainwallet hunting tools or bitcoin mixers which are discussed plenty..
It could be a scam and has no reputation? The nature of the tool makes it hard to prove not, but you can't build a reputation without starting from 0. Again, bitcoin mixers, trading and other tools discussed here have similar potential problems.

-> How? If mods want to censor a post, is it not normal practice to just remove the link, or at least give a notice to the op? I find it really odd there is no trace of the post or its removal.

If it was not moderated, is there a bug that caused my post to be lost?