Can it be true that sometimes posts are removed without any notification? You would at least expect a PM or a notification inside the thread from a moderator?
AFAIK you either get a PM or the mod will post in the thread something similar to "off topic posts removed, please stay on topic"
Typically, that is true. However, sometimes when a removal notice has already been posted in a thread, and additional posts get made that continue in the same fashion, we won't repeat the same notice again and again. Also, if a post is really obviously off-topic, like maybe a joke of some sort, we might not think notification is necessary.
@ SweX, that is what I was thinking also. This one I understand. This one feels a bit weird, I would advice you to at least let mods PM that someone. Perhaps I´m just crazy but I believe this happened to me at least 3 times this year. My latest post that was removed (at least I believe so) was indeed a bit of a joke, but still related to the topic.